Glutamate and Its Receptors in CNS
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Glutamate and Its Receptors in CNS

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Questions and Answers

Which of the following neurotransmitters is considered the principal inhibitory amino acid in the CNS?

  • Asparagine
  • Serotonin
  • Glycine (correct)
  • L-Glutamate

    • How does excessive glutamate affect neurons?

  • It causes excitotoxic effects leading to cell death. (correct)
  • It promotes the uptake of GABA.
  • It decreases neuronal excitability.
  • It enhances synaptic transmission.

    • What is the main function of GABA in the central nervous system?

  • To modulate synaptic transmission through inhibitory mechanisms. (correct)
  • To increase neuronal firing rates.
  • To enhance glutamate receptor activation.
  • To facilitate long-term potentiation.

    • NMDA receptors are notably characterized by their high permeability to which ion?

    <p>Ca2+</p> Signup and view all the answers

    Metabotropic glutamate receptors primarily function to inhibit which enzyme class?

    <p>Adenylate cyclase</p> Signup and view all the answers

    Glycine primarily functions as which type of neurotransmitter?

    <p>Inhibitory</p> Signup and view all the answers

    Which drug target is particularly associated with long-term adaptive changes in the brain?

    <p>NMDA receptors</p> Signup and view all the answers

    Purines in neurotrasmission are primarily involved in what type of signaling?

    <p>Excitatory signaling.</p> Signup and view all the answers

    What is the primary role of glycine as a neurotransmitter in the central nervous system?

    <p>Inhibiting neuronal excitability</p> Signup and view all the answers

    In what way do methylxanthines, such as caffeine, influence adenosine receptors?

    <p>They act as agonists on A1 receptors</p> Signup and view all the answers

    How does strychnine affect glycine's function in the nervous system?

    <p>It blocks glycine’s inhibitory response</p> Signup and view all the answers

    Which effect does adenosine primarily exert on neural activity?

    <p>It has a sedative effect on the CNS</p> Signup and view all the answers

    What physiological role does nitric oxide serve in neuronal function?

    <p>It can produce both inhibitory and excitatory effects</p> Signup and view all the answers

    What is a function of histamine in the central nervous system?

    <p>Modulation of wakefulness and alertness</p> Signup and view all the answers

    How do H1 receptor antagonists primarily function in relation to histamine?

    <p>They have sedative and antiemetic effects</p> Signup and view all the answers

    What potential therapeutic use have GlyT2 inhibitors shown?

    <p>They could serve as analgesics</p> Signup and view all the answers

    Which type of neurotransmitter is primarily associated with the inhibition of neuronal activity in the central nervous system?

    <p>GABA</p> Signup and view all the answers

    What is the primary role of glycine in neurotransmission?

    <p>To act as an inhibitory neurotransmitter</p> Signup and view all the answers

    Which of the following drugs is known to primarily influence noradrenergic transmission?

    <p>Cocaine</p> Signup and view all the answers

    What role do purines play in neurotransmission?

    <p>They are important modulators of synaptic transmission.</p> Signup and view all the answers

    What is a common misconception about GABA's function in the CNS?

    <p>GABA is an excitatory neurotransmitter.</p> Signup and view all the answers

    Which neurotransmitter is primarily involved in movement control and is deficient in Parkinson's disease?

    <p>Dopamine</p> Signup and view all the answers

    What misconception exists regarding the action of antidepressants on neurotransmitters?

    <p>They only affect serotonin levels.</p> Signup and view all the answers

    What is another name for excitatory neurotransmitters, which includes certain amino acids?

    <p>Aminoacid transmitters</p> Signup and view all the answers

    Which of the following actions is primarily associated with adrenalin in high doses?

    <p>Vasoconstriction</p> Signup and view all the answers

    What is a known effect of administering dopamine at small doses?

    <p>Vasodilation</p> Signup and view all the answers

    Which receptor is primarily activated by epinephrine in the treatment of anaphylaxis?

    <p>β2 receptors</p> Signup and view all the answers

    What physiological response does norepinephrine primarily induce?

    <p>Increased blood pressure</p> Signup and view all the answers

    In addition to its vasodilatory effects, what else can dopamine stimulate?

    <p>Increased urinary output</p> Signup and view all the answers

    Which adrenergic action is indicative of β2 stimulation in low doses?

    <p>Broncodilation</p> Signup and view all the answers

    What is a typical adverse effect of high doses of catecholamines, like adrenaline?

    <p>Arrhythmias</p> Signup and view all the answers

    What common cardiovascular effect can be experienced with the use of β-agonists?

    <p>Tachycardia</p> Signup and view all the answers

    What complication can arise from excessive stimulation of adrenergic receptors?

    <p>Psychomotor agitation</p> Signup and view all the answers

    What effect on blood pressure results from low doses of vasopressors like norepinephrine?

    <p>Hypertension</p> Signup and view all the answers

    Which physiological change is least likely associated with α-adrenergic stimulation?

    <p>Increased heart rate</p> Signup and view all the answers

    Which response is associated with β1 receptor activity?

    <p>Increased cardiac output</p> Signup and view all the answers

    What effect may occur from blocking β1 receptors in patients with heart failure?

    <p>Decreased heart rate</p> Signup and view all the answers

    Which mechanism is primarily responsible for the side effects seen with excessively high doses of catecholamines?

    <p>Overstimulation of adrenergic receptors</p> Signup and view all the answers

    Which effect is least likely to be a direct result of catecholamine administration?

    <p>Increased gastrointestinal motility</p> Signup and view all the answers

    Which of the following medications primarily functions as a selective serotonin reuptake inhibitor (SSRI)?

    <p>Fluoxetine</p> Signup and view all the answers

    Which tricyclic antidepressant (TCA) is often associated with significant anticholinergic side effects?

    <p>Amitriptyline</p> Signup and view all the answers

    Which of the following statements best represents the metabolism of SSRIs?

    <p>SSRIs generally undergo extensive first-pass metabolism.</p> Signup and view all the answers

    Which of the following is NOT a common symptom of serotonin syndrome?

    <p>Hypoglycemia</p> Signup and view all the answers

    What is a major side effect associated with SSRIs that affects gastrointestinal health?

    <p>Nausea</p> Signup and view all the answers

    Which side effect is commonly associated with TCA medications?

    <p>Dry mouth</p> Signup and view all the answers

    Which SSRI is specifically noted for efficacy in treating obsessive-compulsive disorder?

    <p>Sertraline</p> Signup and view all the answers

    What is a critical adverse effect to consider when prescribing a combination of SSRIs and MAO inhibitors?

    <p>Serotonin syndrome</p> Signup and view all the answers

    Which of the following is a potential side effect of discontinuing SSRI medication abruptly?

    <p>Withdrawal symptoms</p> Signup and view all the answers

    Which of the following medications can increase the risk of serotonin syndrome when combined with SSRIs?

    <p>Sumatriptan</p> Signup and view all the answers

    TCA medications are known to primarily act on which neurotransmitter systems?

    <p>Serotonin and norepinephrine</p> Signup and view all the answers

    Which SSRI is often preferred for its relatively favorable side effect profile?

    <p>Escitalopram</p> Signup and view all the answers

    What is the mechanism of action of most SSRIs?

    <p>Inhibiting serotonin reuptake</p> Signup and view all the answers

    Which class of medications primarily inhibits the reuptake of serotonin and is commonly prescribed for depression?

    <p>Selective Serotonin Reuptake Inhibitors (SSRI)</p> Signup and view all the answers

    What is a common side effect associated with Tricyclic Antidepressants (TCA)?

    <p>Dry mouth</p> Signup and view all the answers

    Which medication is known to be effective in treating anxiety disorders by increasing norepinephrine and serotonin?

    <p>Venlafaxine</p> Signup and view all the answers

    What is a serious condition that can arise from an interaction between SSRIs and certain other medications leading to excessive serotonin levels?

    <p>Serotonin Syndrome</p> Signup and view all the answers

    Which of the following is a possible side effect of bupropion?

    <p>Seizures at high doses</p> Signup and view all the answers

    Which antidepressant class is specifically known to cause anticholinergic side effects?

    <p>TCAs</p> Signup and view all the answers

    How do Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) primarily exert their clinical effects?

    <p>By inhibiting reuptake of both serotonin and norepinephrine</p> Signup and view all the answers

    Which of the following SSRIs is most commonly prescribed for anxiety and depression symptoms?

    <p>Sertraline</p> Signup and view all the answers

    What is the mechanism of action of MAO inhibitors?

    <p>Inhibiting monoamine oxidase activity</p> Signup and view all the answers

    Which of the following is NOT a typical side effect of SSRIs?

    <p>Hyperactivity</p> Signup and view all the answers

    What change in serotonin and norepinephrine levels is most commonly seen with the administration of SNRIs?

    <p>Increase in both serotonin and norepinephrine</p> Signup and view all the answers

    Which TCA is often prescribed for its sedative properties and is typically used for both depression and anxiety?

    <p>Amitriptyline</p> Signup and view all the answers

    What major side effect is closely associated with the use of MAOIs?

    <p>Hypertensive crisis when ingesting tyramine</p> Signup and view all the answers

    What is the mechanism of action for Tetradotoxin?

    <p>Blocks Na channels</p> Signup and view all the answers

    What does Batrotoxin do?

    <p>Keeps K channels open</p> Signup and view all the answers

    Dopamine in small doses causes vasodilation.

    <p>True</p> Signup and view all the answers

    Adrenaline primarily acts on __________ receptors to increase heart rate.

    <p>beta-1</p> Signup and view all the answers

    What are the potential adverse effects of adrenaline?

    <p>Panic</p> Signup and view all the answers

    What is the classification of D1 receptor?

    <p>Dopaminergic receptor</p> Signup and view all the answers

    Norepinephrine promotes vasodilation.

    <p>False</p> Signup and view all the answers

    Acetylcholine action is degraded by __________.

    <p>acetylcholinesterase</p> Signup and view all the answers

    What does 'Oxybutynin' primarily treat?

    <p>Overactive bladder</p> Signup and view all the answers

    Which of the following medications is an anticholinergic?

    <p>Oxybutynin</p> Signup and view all the answers

    Fluoxetine is a selective serotonin reuptake inhibitor (SSRI).

    <p>True</p> Signup and view all the answers

    What is the mechanism of action of Pizotifen?

    <p>5-HT2 antagonist</p> Signup and view all the answers

    Match the following medications with their uses:

    <p>Oxybutynin = Overactive bladder Fluoxetine = Depression Pizotifen = Migraine prophylaxis Ondansetron = Nausea and vomiting due to chemotherapy</p> Signup and view all the answers

    ____ is a medication used to inhibit acetylcholinesterase in myasthenia gravis.

    <p>Neostigmine</p> Signup and view all the answers

    What does 'malignant' refer to?

    <p>Cancerous</p> Signup and view all the answers

    Hypertensive refers to low blood pressure.

    <p>False</p> Signup and view all the answers

    What is bradycardia?

    <p>Condition of slow heart rate</p> Signup and view all the answers

    What is the effect of atropine?

    <p>Increases heart rate and reduces secretions.</p> Signup and view all the answers

    Which of these symptoms can be caused by scopolamine?

    <p>Drowsiness</p> Signup and view all the answers

    What does 'antiemetic' mean?

    <p>A drug that prevents nausea and vomiting.</p> Signup and view all the answers

    What does 'miosis' refer to?

    <p>Constricted pupils</p> Signup and view all the answers

    Tachycardia refers to a slow heartbeat.

    <p>False</p> Signup and view all the answers

    The condition of high blood pressure is known as __________.

    <p>hypertension</p> Signup and view all the answers

    β-blockers are used to treat __________.

    <p>hypertension</p> Signup and view all the answers

    Which of the following are effects of β-blockers? (Select all that apply)

    <p>Decreased heart rate</p> Signup and view all the answers

    β-blockers have no effect on bronchial constriction.

    <p>False</p> Signup and view all the answers

    What is one contraindication for the use of β-blockers?

    <p>asthma</p> Signup and view all the answers

    Alprenolol, a type of β-blocker, primarily acts as a __________ antagonist.

    <p>β1 adrenergic</p> Signup and view all the answers

    Which β-blocker has mixed action?

    <p>Carvedilol</p> Signup and view all the answers

    All β-blockers have a long duration of action.

    <p>False</p> Signup and view all the answers

    Name a clinical use of beta-blockers.

    <p>heart failure management</p> Signup and view all the answers

    Methyldopa is primarily used for __________ management during pregnancy.

    <p>hypertension</p> Signup and view all the answers

    Which drug is known for its anesthetic properties?

    <p>Cocaine</p> Signup and view all the answers

    Tubocurarine can lead to respiratory paralysis.

    <p>True</p> Signup and view all the answers

    What is the effect of Suxamethonium on the body?

    <p>neuromuscular blockade</p> Signup and view all the answers

    Which medication is associated with the treatment of epilepsy?

    <p>Gabapentin</p> Signup and view all the answers

    Gabapentin is primarily used for treating migraines.

    <p>False</p> Signup and view all the answers

    What is the purpose of migraine prophylactic medications?

    <p>To prevent migraine attacks</p> Signup and view all the answers

    The medication Gabapentin is often prescribed for _____.

    <p>epilepsy</p> Signup and view all the answers

    Which of the following medications is classified as an α1 agonist?

    <p>Phenypropamine</p> Signup and view all the answers

    Ritodrine is a β2 agonist.

    <p>True</p> Signup and view all the answers

    What is the duration of action for Phenoxybenzamine?

    <p>12h</p> Signup and view all the answers

    _____ is a medication used primarily to relieve nasal congestion.

    <p>Pseudoephedrine</p> Signup and view all the answers

    Match the following medications to their classifications:

    <p>Dobutamine = β1 agonist Ritodrine = β2 agonist Clonidine = α2 agonist Phenoxybenzamine = Non-selective α antagonist</p> Signup and view all the answers

    What type of receptor does Yohimbine act on?

    <p>α2 antagonist</p> Signup and view all the answers

    What is the main therapeutic effect of Amphetamine?

    <p>Increased alertness</p> Signup and view all the answers

    Phentolamine is a selective α antagonist.

    <p>False</p> Signup and view all the answers

    Which medication is used as a nasal decongestant and acts as a vasoconstrictor?

    <p>Xylometazoline</p> Signup and view all the answers

    Ergotamine is derived from ergot fungus and used to treat migraines.

    <p>True</p> Signup and view all the answers

    What is the primary use of Salbutamol?

    <p>Bronchodilator</p> Signup and view all the answers

    What is the action of Methylenedioxymethamphetamine (MDMA)?

    <p>All of the above</p> Signup and view all the answers

    Selective serotonin reuptake inhibitors (SSRIs) mainly target dopamine reuptake.

    <p>False</p> Signup and view all the answers

    What is a common side effect of tricyclic antidepressants?

    <p>Weight gain</p> Signup and view all the answers

    The primary mechanism of action for MAOIs is to inhibit _____ enzymes.

    <p>monoamine oxidase</p> Signup and view all the answers

    Match the following antidepressants with their classifications:

    <p>Fluoxetine = SSRI Amitriptyline = TCA Phenelzine = MAOI Venlafaxine = SNRI</p> Signup and view all the answers

    What is the primary use of Bupropion?

    <p>Antidepressant</p> Signup and view all the answers

    Atypical antidepressants do not affect serotonin levels.

    <p>False</p> Signup and view all the answers

    What condition is St. John's Wort commonly used to treat?

    <p>Depression</p> Signup and view all the answers

    The medications Venlafaxine and Duloxetine are classified as _____ inhibitors.

    <p>SNRI</p> Signup and view all the answers

    Which of the following is a side effect of SSRIs?

    <p>All of the above</p> Signup and view all the answers

    MAOIs can cause hypertensive crisis if the patient consumes _____ foods.

    <p>tyramine-rich</p> Signup and view all the answers

    What is the function of 5HT2C receptor?

    <p>It is involved in mood regulation and appetite.</p> Signup and view all the answers

    What do antipsychotics generally target?

    <p>Dopamine receptors.</p> Signup and view all the answers

    Which neurotransmitters are affected by lithium?

    <p>All of the above</p> Signup and view all the answers

    Valproate is known to increase sedation?

    <p>True</p> Signup and view all the answers

    What is a common side effect of antiepileptic drugs?

    <p>All of the above</p> Signup and view all the answers

    What is the mechanism of action of SSRIs?

    <p>Serotonin reuptake inhibitor</p> Signup and view all the answers

    Lithium is primarily used to treat ________ disorder.

    <p>bipolar</p> Signup and view all the answers

    What does the abbreviation BZD stand for?

    <p>Benzodiazepines.</p> Signup and view all the answers

    Which of the following is a side effect of Olanzapine?

    <p>All of the above</p> Signup and view all the answers

    Carbamazepine is a type of antidepressant?

    <p>False</p> Signup and view all the answers

    Study Notes

    Glutamate: The Main Excitatory Neurotransmitter

    • L-Glutamate is the primary excitatory amino acid transmitter (EAA) in the central nervous system (CNS).
    • Glutamate synthesis pathways are intertwined with those for inhibitory amino acids, GABA and glycine, meaning disturbances in one pathway can affect both excitatory and inhibitory neurotransmission.
    • Glutamate is stored in synaptic vesicles and released into the synapse.
    • After release, glutamate is taken up by nerve terminals and astrocytes.
    • Astrocytes convert glutamate to glutamine.
    • Glutamate is produced from glucose or by glutamine hydrolysis.
    • Glutamate activates both ionotropic (ligand-gated cation channels) and metabotropic (G protein-coupled) receptors.
    • Excess glutamate can lead to excitotoxicity and cell death, especially in situations like ischemia.

    Glutamate Receptors: Ionotropic and Metabotropic

    • Ionotropic glutamate receptors are classified based on their glutamate affinity:

      • NMDA receptors: High affinity, highly permeable to calcium ions (Ca2+). Blocked at resting potential by magnesium ions (Mg2+). Voltage-dependent removal of the Mg2+ block activates the receptor, mediating slow synaptic responses.
      • Non-NMDA receptors: Permeable to sodium (Na+) and potassium (K+), low permeability to Ca2+.
        • AMPA receptors: Mediate rapid synaptic transmissions.
        • Kainate receptors: Mediate slow synaptic transmissions.

    • Metabotropic glutamate receptors (mGluRs):

      • Eight types divided into three groups:
        • Group I (mGluR1, R5): Activate phospholipase C.
        • Group II (mGluR2, R3) and Group III (mGluR4, R6, R7, R8): Inhibit adenylate cyclase.

    NMDA and mGlu Receptors: Importance in Brain Function

    • NMDA and mGlu receptors play crucial roles in long-term brain adaptation, including both beneficial and pathological changes.
    • They are potential targets for drug development.

    The Effects of Glutamate

    • Glutamate activates "reward pathways” in the brain.
    • Low doses of glutamate can lead to euphoria and well-being.
    • High doses of glutamate can cause depression of the CNS and loss of consciousness.

    Glycine: An Inhibitory Neurotransmitter

    • Glycine is an essential inhibitory neurotransmitter in the spinal cord and brain stem.
    • Strychnine, a glycine antagonist, is a convulsant poison that blocks glycine's function.
    • Tetanus toxin prevents glycine release, leading to excessive reflex hyperexcitability and muscle spasms.
    • GlyT2 inhibitors have potential as analgesics.

    Adenosine: An Inhibitory Modulator

    • Adenosine exerts mainly inhibitory effects on adenosine receptors A1 and A2, leading to sedative, anticonvulsant, and neuroprotective effects.
    • Adenosine acts as a safety mechanism.
    • Methylaxanthines, such as caffeine, are agonists on A1 receptors and increase wakefulness.

    Histamine: A Waking Neurotransmitter

    • Histamine's functions in the CNS are not fully understood.
    • Histaminergic neurons are active during wakefulness.
    • H1 receptor antagonists are strongly sedative, and some H1 receptor antagonists are used as antiemetic drugs (to prevent vomiting).

    Melatonin: A Sleep-Promoting Neurotransmitter

    • Melatonin acts on melatonin receptors M1 and M2 in the CNS.
    • Melatonin receptor agonists induce sleep and have antidepressant properties.

    Nitric Oxide (NO): A Modulator of Neuronal Function

    • NO affects neuronal function by increasing cGMP formation, producing both inhibitory and excitatory effects on neurons.

    Antidepressants

    • Tricyclic Antidepressants (TCAs) are a class of antidepressants with a tricyclic molecular structure.
      • They are lipophilic and taken orally.
      • They inhibit reuptake of dopamine, norepinephrine, and serotonin in the brain.
      • TCAs have a long half-life of 10-80 hours.
      • They have orthostatic hypotension and no catecholamine effect.
      • Cross the Blood Brain Barrier (BBB)
      • They are frequently used in the treatment of depression, anxiety, and pain syndromes.
      • TCAs have a high risk of overdose
        • Anticholinergic effects like
          • Antihypertensive,
          • Palpitation,
          • Tachycardia,
          • Tremor,
          • Convulsions, and
          • Coma
        • Cardiovascular
          • Warfarin Interactions
          • Bleeding
        • Alcohol interactions
        • Anersthetics interactions
        • Oral Contraception interactions
    • Selective Serotonin Reuptake Inhibitors (SSRIs) are a class of antidepressants that selectively inhibit the reuptake of serotonin in the brain.
      • They are orally administered
      • Selective Serotonin Reuptake Inhibitors (SSRIs) have a short half-life of 15-25 hours.
      • They are frequently used in the treatment of depression, anxiety, obsessive-compulsive disorder, panic disorder, premenstrual dysphoric disorder, bulimia nervosa, and migraine headaches.
      • SSRIs have few adverse drug reactions (ADRs) when compared to TCAs.
      • Anticholinergic effects like
        • Nausea,
        • Anorexia,
        • Insomnia,
        • Loss of libido,
        • Serotonin Syndrome (summation of drugs affecting serotonin)
      • Cardiovascular effects like
        • Ventricular arrhythmia,
        • Collapses,
        • Death
      • Potential for aggression and suicidal ideation
    • Monoamine Oxidase Inhibitors (MAOIs) are a class of antidepressants that inhibit the enzyme monoamine oxidase, which breaks down neurotransmitters like serotonin, norepinephrine, and dopamine.
      • MAOIs are nonselective (inhibit both MAO-A and MAO-B) and irreversible.
      • Short-acting
      • They are frequently used in the treatment of depression, anxiety, and Parkinson's disease.
      • MAOIs have a high risk of adverse effects
        • Tyramine interactions
          • Orthostatic hypotension,
          • Hypertensive crisis,
          • Excessive CNS stimulation,
          • Tremor,
          • Excitement,
          • Insomnia,
          • Overdose,
          • Convulsions,
          • Headaches,
          • Chest pain,
          • Nausea,
          • Vomiting,
          • Sweating, and
          • Tachycardia
        • No TCA interaction
    • Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) are a class of antidepressants that inhibit the reuptake of both serotonin and norepinephrine in the brain.
      • SNRIs are orally administered and inhibit the uptake of serotonin and NA.
      • They are frequently used in the treatment of major depressive disorder, generalized anxiety disorder, and some types of chronic pain.
      • SNRIs have a high risk of adverse effects
        • Headaches,
        • Insomnia,
        • Sexual dysfunction,
        • Dry mouth,
        • Dizziness,
        • Sweating,
        • Decreased appetite,
        • CNS
        • Serotonin Syndrome
        • Cardiovascular
        • Hepatopathy
    • Bupropion is an atypical antidepressant that is not a typical SSRI, SNRI, or MAOI.
      • Bupropion is orally administered and inhibits the reuptake of dopamine and norepinephrine
      • Bupropion is frequently used in the treatment of depression, seasonal affective disorder, and nicotine addiction.
      • Bupropion has a moderate risk of side effects
        • Increased doses lead to seizures
        • Potential for Abuse
    • Reboxetine is an atypical antidepressant that is not a typical SSRI, SNRI, or MAOI.
      • Reboxetine is orally administered and selectively inhibits the reuptake of norepinephrine.
      • Reboxetine is frequently used in the treatment of depression.
    • Atomoxetine is a selective norepinephrine reuptake inhibitor (SNRI) that is used to treat attention deficit hyperactivity disorder (ADHD).
      • It is a non-stimulant medication.
      • Atomoxetine is orally administered and selectively inhibits the reuptake of norepinephrine.
      • It is often used for patients with ADHD who cannot tolerate stimulants or for whom stimulants are ineffective.
      • It is often used in conjunction with behavioral therapy.

    Other Medications

    • Methylxanthines drugs are antagonists of the A1 adenosine receptor
      • Caffeine (part of the methylxanthine family) increases alertness, wakefulness and decreases fatigue.

    Respiratory System

    • Ipratropium (Ipratropium bromide) is an anticholinergic bronchodilator.
    • Tiotropium is a long-acting anticholinergic (quaternary derivative).
    • Both Ipratropium and Tiotropium are used for the treatment of asthma.
    • Some side effects of Ipratropium and Tiotropium include: dry mouth; urinary difficulty.

    Allergic Reactions

    • Pirenzepine is an antagonist of the M1 subtype of the muscarinic acetylcholine receptor.
    • Pirenzepine is used to treat acid reflux, gastritis, and other stomach problems.
    • It also inhibits acetylcholine secretion (M1).

    Urinary System

    • Oxybutynin is an anticholinergic medication.
    • Tolterodine is an anticholinergic medication.
    • Both Oxybutynin and Tolterodine are used to treat overactive bladder.

    Cholinergic Agonists

    • Carbachol is a parasympathomimetic, meaning it mimics the effects of acetylcholine.
    • Carbachol is used to treat glaucoma.
    • Some side effects of Carbachol include: bradycardia, bronchospasm, GI upset, and headaches.

    Muscarinic Antagonists

    • Pilocarpine is a parasympathomimetic medication.
    • Pilocarpine is used to treat dry mouth (xerostomia), and glaucoma.
    • Pilocarpine has a higher affinity for M3 receptors compared to M1 receptors.
    • Common side effects include: headache, sweating, and flushing.
    • Cevimeline is another drug that acts like Pilocarpine.
    • Cevimeline is a synthetic cholinergic agonist drug.

    Anticholinesterase

    • Neostigmine is a cholinesterase inhibitor, that is given by IV or SC injection.
    • Physostigmine is a short-acting reversible cholinesterase inhibitor.
    • Edrophonium is a short-acting reversible cholinesterase inhibitor.
    • Ambenonium is a long-acting, reversible cholinesterase inhibitor.
    • Neostigmine, Physostigmine, Edrophonium, and Ambenonium are all reversible cholinesterase inhibitors.

    Irreversible Cholinesterase Inhibitor

    • Ecothiophate is an irreversible cholinesterase inhibitor.
    • Parathion is an irreversible cholinesterase inhibitor.

    Serotonin

    • Buspirone is a serotonin 5-HT1A agonist, which is useful for treating anxiety.
    • Fluoxetine is a selective serotonin reuptake inhibitor, useful for treating depression.
    • Triptans (including Sumatriptan) are selective serotonin 5-HT1D agonists, useful for the treatment of migraines.
    • Pizotifen is a 5-HT2 antagonist.
    • Ondansetron is a 5-HT3 antagonist, useful for treating chemotherapy-induced nausea and vomiting.

    Others

    • HDMA is a mood altering drug (hallucinogenic).
    • Ketamine is an NMDA receptor antagonist.
    • Memantine is an NMDA receptor antagonist, useful for treating Parkinson's disease.
    • Bicuculline is a GABA receptor antagonist.
    • Baclofen is a GABAb agonist, useful for treating spasticity, drug dependency, and other conditions.
    • Strychnine, a glycine antagonist, is a powerful neurotoxin.

    ### Adrenaline

    • Administered intravenously, subcutaneously, intramuscularly, and by inhalation
    • Adrenergic effects:
      • β1: Increases heart rate, contractility, and blood pressure (systolic)
      • α: Vasoconstriction (high doses), leading to increased blood pressure, heart rate, and contractility
      • β2: Smooth muscle relaxation (bronchodilation, metabolic effects, uterine relaxation, GI relaxation)
    • Indications: Cardiac arrest, anaphylaxis, shock, haemorrhages, nasal decongestant, anaesthesia, angioedema
    • Weaknesses: Panic/anxiety, tremors, cerebral vasoconstriction, arrhythmias, no crossing blood-brain barrier

    NA / NE

    • Administered intravenously, intramuscularly
    • Alpha and beta adrenergic agonist effects:
      • α: Vasoconstriction, leading to increased blood pressure, heart rate, and contractility
      • β: Increased heart rate, contractility, and blood pressure; may also increase myocardial oxygen demand
    • Indications: Local bleeding, hypotension (including anaphylactic shock), topical nasal decongestant
    • Weaknesses: Tachycardia (risk of necrosis), arrhythmias, hypertension, hyperthermia, no crossing blood-brain barrier, quick elimination
    • May cause:
      • Tachycardia
      • Arrhythmias
      • Hypertension
      • Hyperthermia
      • Necrosis
      • Bleeding
        • Local haemorrhage from IV injection

    Dopamine

    • Administered intravenously
    • D1 receptor activation - small doses: Vasodilation
    • D1 and D2 receptor activation - high doses: Inotropic and chronotropic effects (increase heart rate and contractility)
    • Indications: Shock, low cardiac output, cardiac arrest
    • Weaknesses: No major weaknesses listed, but careful monitoring and dose adjustments are important

    Neurotoxins

    • Tetrodotoxin (pufferfish) blocks sodium channels leading to paralysis and respiratory failure

    Cardiotoxins

    • Batrachotoxin (frog/fish) keeps potassium channels open persistently leading to depolarization, causing convulsions, spasms, and paralysis.
    • Snake Venom blocks acetylcholine receptors, prevents muscle contraction, and degrades acetylcholine, leading to muscle weakness.

    Adrenaline/Epinephrine

    • Administered intravenously, subcutaneously, intramuscularly, and via inhalation.
    • Non-selective catecholamine adrenergic.
    • Beta-1 receptors in the heart cause vasoconstriction (high dose), increased heart rate and blood pressure, and heart block.
    • Beta-2 receptors (low dose) promote smooth muscle relaxation and bronchodilation.
    • Alpha-1 receptors (high dose) cause vasoconstriction, panic, anxiety, tremors, and cerebral vasoconstriction.
    • It can cause arrhythmias, haemorrhages, and hyperglycemia.
    • Used for anaphylaxis (allergy), angio-oedema, and uterine contractions.
    • Has no effect on crossing the blood brain barrier.

    NA/NE

    • Administered intravenously and intramuscularly.
    • Agonist at alpha and beta receptors.
    • Can cause vasoconstriction, increased blood pressure, tachycardia causing arrhythmias, hypertension (necrosis/bleeding), and hyperthermia.
    • It can also cause local bleeding, and anaphylactic shock.
    • Used for topical nasal decongestants and has no effect on crossing the blood brain barrier.

    Dopamine

    • Administered intravenously.
    • Small doses act on Dopamine-1 receptors in the renal and heart, causing vasodilation.
    • Moderate doses target beta-1 receptors causing vasoconstriction.
    • High doses target alpha-1 receptors causing vasoconstriction, and reduction in renal blood flow
    • Does not cross the blood brain barrier

    β-blockers

    • β-blockers: Used for Angina, Hypertension, Heart Failure, Arrhythmias
    • β-blockers: Oral and Parenteral routes
    • β-blockers: Mechanism: β-receptor antagonists
    • β-blockers: Effects: Decrease Heart Rate (HR), Blood Pressure (BP), Contractility, Cardiac Output (CO), Oxygen demand, Intraocular Pressure
    • β-blockers: Side Effects: Bradycardia, AV-block, Bronchospasm (non-selective), Raynaud's, CNS insomnia, depression, tiredness, dizziness, decreased libido
    • β-blockers: Contraindicated: Asthma, Heart Block, Uncompensated Heart Failure, Insulin-dependent diabetes, Bradycardia
    • β-blockers: Types:
      • Propranolol: Non-selective, long half-life (5 hours), used for atrial fibrillation and hypertension
      • Alprenolol: Mixed β-receptor antagonist (β1, β2)
      • Oxprenolol: Mixed β-receptor antagonist (β1, β2)
      • Atenolol: β1-selective, short half-life
      • Nebivolol: β1-selective antagonist

    α-methyltyrosine

    • α-methyltyrosine: Inhibits the synthesis of Noradrenaline (NA)
    • α-methyltyrosine: Used for Pheochromocytoma

    L-DOPS

    • L-DOPS: Increases synthesis of dopamine
    • L-DOPS: Used for Parkinson's disease

    Methyldopa

    • Methyldopa: Reduces synthesis of noradrenaline
    • Methyldopa: Used for pregnancy hypertension
    • Methyldopa: Can reduce antihypertensive effect

    Imiprimine

    • Imiprimine: Inhibits the reuptake of Noradrenaline (NA) and serotonin
    • Imiprimine: Used for depression
    • Imiprimine: Can cause cardiac dysrhythmias, OD, Atropine-like effects

    Cocaine

    • Cocaine: Inhibits the reuptake of Noradrenaline (NA) and dopamine
    • Cocaine: Used for local anesthesia
    • Cocaine: Abuse can lead to Hyperthermia, convulsions, and dependence

    Tubocurarine

    • Tubocurarine: Inhibits nicotinic cholinergic receptors
    • Tubocurarine: Used for muscle relaxation, paralysis
    • Tubocurarine: Can cause respiratory paralysis, bronchospasm

    Pancuronium

    • Pancuronium: Competitive antagonist of acetylcholine at nicotinic receptors
    • Pancuronium: Used for muscle relaxation during anesthesia
    • Pancuronium: Can cause hypotension, tachycardia

    Suxamethonium

    • Suxamethonium: Depolarizing muscle relaxant (long-acting)
    • Suxamethonium: Used for rapid sequence intubation
    • Suxamethonium: Can cause cardiac arrest

    Succinylcholine

    • Succinylcholine: Depolarizing muscle relaxant (short-acting)
    • Succinylcholine: Can cause hyperthermia, anaphylactic shock, malignant hyperthermia
    • Succinylcholine: Used for intubation, electroconvulsive therapy, paralysis

    Dantrolene

    • Dantrolene: Inhibits calcium release from sarcoplasmic reticulum
    • Dantrolene: Used for malignant hyperthermia
    • Dantrolene: Side Effects: Weakness, fatigue, drowsiness, hepatotoxicity

    Anticholinergic Agents

    • Anticholinergic agents are medications that block the action of acetylcholine (ACh), a neurotransmitter in the parasympathetic nervous system.
    • They are used to treat a variety of conditions, including:
      • Parkinson's disease
      • Asthma
      • Bladder control problems
      • Motion sickness
      • Nausea and vomiting
      • Eye conditions
      • Bradycardia (slow heart rate).

    Mechanisms of Action

    • Inhibit the Muscarinic Receptor: Anticholinergics bind to muscarinic receptors, blocking the effects of ACh.
    • Competitive or Non-competitive Inhibition: Anticholinergics can competitively bind to the receptor, preventing ACh from interacting. Sometimes, non-competitive inhibition occurs where the drug binds to the receptor irreversibly.
    • Postganglionic Neuronal Blocking: Block the action of ACh at the postganglionic neurons of the parasympathetic nervous system.

    Types of Anticholinergic Drugs

    • Trimetafan: Inhibits nicotinic receptors at the postganglionic neurons of the autonomic nervous system.
    • Atropine: Inhibits muscarinic receptors, causing increased heart rate, dry mouth, dilated pupils, constipation, and urinary retention.
    • Scopolamine: Inhibits muscarinic receptors, causing anti-nausea effects, blurred vision, and drowsiness.
    • Methylamphetamine: Inhibits muscarinic receptors, causing anti-Parkinsonian symptoms.
    • Benztropine: Inhibits muscarinic receptors, used in the treatment of Parkinson's disease.
    • Methyscopolamine: Inhibits muscarinic receptors, primarily used for treatment of ulcers, gastroparesis, and motion sickness.

    Adverse Effects

    • Dry Mouth: Inhibition of salivary glands.
    • Blurred Vision: Dilated pupils impair accommodation.
    • Constipation: Reduced gut motility.
    • Urinary Retention: Reduced bladder muscle control.
    • Tachycardia: Increased heart rate.
    • Glaucoma: Increased intraocular pressure.
    • Allergic reactions: In some individuals, anticholinergics can cause allergic reactions.

    Toxicity

    • Overdose: Can cause delirium, seizures, and coma.
    • Anticholinergic Crisis: Life threatening condition, characterized by severe symptoms, including confusion, hallucinations, fever, and rapid heart rate.

    Contraindications

    • Individuals with glaucoma, bowel obstruction, urinary retention, prostatic hypertrophy, and myasthenia gravis should avoid using anticholinergic medications.
    • Pregnancy and Breastfeeding: Use with caution during pregnancy and breastfeeding, consult with a healthcare professional.

    Important Considerations

    • Dosing: Dosing adjustments may be needed for individuals younger than 18 years old or those with renal or hepatic impairment.
    • Drug Interactions: Anticholinergics can interact with other medications, especially those affecting the nervous system, heart rate, and liver function.
    • Monitoring: Monitor for adverse effects while on anticholinergic medications.

    Respiratory

    • Ipratropium (Ipratropium bromide) - Treats asthma. It is a short-acting muscarinic antagonist.
    • Tiotropium (quaternary derivative of atropine) - Treats asthma. It is a long-acting muscarinic antagonist.
    • Pirenzepine - Inhibits Acetylcholine secretion (M1).

    Urology

    • Oxybutynin & Tolterodine - Overactive bladder, this is an anticholinergic drug.

    GI

    • Carbachol - An acetylcholine analogue, It acts as an agonist at the muscarinic receptors M1, M2, M3, and M4.
    • Bethanechol - This is an acetylcholine muscarinic receptor agonist, it works by stimulating GI motility in the esophagus, stomach, and small intestine.

    Eye

    • Pilocarpine - Treats glaucoma and xerostomia. It is an Ach agonist. It can cause systemic effects in high concentrations because it penetrates the blood-brain barrier, thus causing the adverse effects of cholinergic overdose.

    Neuro

    • Neostigmine , Physostigmine, Edrophonium and Pyridostigmine - Reversing neuromuscular blockade. They are cholinesterase inhibitors. These drugs can be used to treat the effects of neuromuscular blockade.
    • Ambenonium - A reversible neuro-muscular blocker, used in the treatment of Myasthenia Gravis.

    Toxicology

    • Ecothiophate and Parathion - Are potent cholinesterase inhibitors.

    Psychiatry

    • Buspirone - Treats anxiety, it is a serotonin (5HT1a) agonist
    • Fluoxetine - Treats depression. It is a selective serotonin reuptake inhibitor (SSRI).
    • Triptans (Sumatriptan) - Treats migraine headaches. It is a 5-HT1D receptor agonist.
    • Pizotifen - Treats migraine headaches. It is a serotonin 5HT2 antagonist.
    • Ondansetron - Treats chemotherapy induced emesis, it is a 5-HT3 antagonist.
    • HDMA (Ecstasy) - Causes mood alterations.

    Anesthesia and others

    • Ketamine - Used as an anesthetic, it is also a NMDA antagonist.
    • Memantine - Treats Parkinson's. It is a NMDA antagonist.
    • Bicuculline - It's a GABAr antagonist.
    • Baclofen - Treats Spasticity, it is a GABAb agonist.
    • Strychnine - It is a Glycine antagonist. It's an excitatory amino acid.
    • M. (Mechanism of action)
    • Ø (Not)
    • PΣ (Plasma concentration)
    • ↓ (Decreases)
    • ↑ (Increases )
    • *= (Equivalent to, same as)
    • SC (Subcutaneous)
    • IV (Intravenous)
    • BBB (Blood brain barrier)
    • Agonist (Activates)
    • Antagonist (Blocks)
    • ( ) (Parenthesis) - Chemical names

    Antidepressants

    • Tricyclic Antidepressants (TCAs)
      • Mechanism: Inhibit reuptake of dopamine, serotonin, and norepinephrine
      • Mode of Administration: Oral (lipo soluble)
      • Pharmacodynamics:
        • ↑ Wakefulness
        • ↓ Emotional symptoms
        • ↓ Biogenic symptoms
      • Adverse Drug Reactions (ADRs):
        • Orthostatic hypotension
        • Palpitations
        • Tachycardia
        • Tremors
        • Convulsions
        • Coma
        • Weight gain
        • Sweating
        • Photosensitivity
        • Gastrointestinal (GI) side effects
        • Overdose (OD) - Anticholinergic toxicity
      • Interactions:
        • MAOIs
        • Alcohol
        • Anesthetics
    • Selective Serotonin Reuptake Inhibitors (SSRIs)
      • Mechanism: Inhibit reuptake of serotonin
      • Mode of Administration: Oral
      • Pharmacodynamics:
        • Selectively inhibits serotonin reuptake
        • Anxiolytic effects
        • Antidepressant effects
      • ADRs:
        • Nausea
        • Anorexia
        • Insomnia
        • Loss of libido
        • Serotonin syndrome
        • Hyperthermia
        • Ventricular arrhythmia
        • Death
      • Interactions:
        • TCAs
        • MAOIs
    • Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)
      • Mechanism: Inhibit reuptake of serotonin and norepinephrine
      • Mode of Administration: Oral
      • Pharmacodynamics:
        • Reduces nausea
      • ADRs:
        • Headaches
        • Insomnia
        • Sexual dysfunction
        • Dry mouth
        • Dizziness
        • Sweating
        • Decreased appetite
        • Overdose - Serotonin toxicity
        • Convulsions
        • Cardiovascular (CV), Hepatic, and Renal toxicity
    • Monoamine Oxidase Inhibitors (MAOIs)
      • Mechanism: Inhibit monoamine oxidase (MAO), which breaks down neurotransmitters, leading to ↑ levels of dopamine, norepinephrine, and serotonin
      • Mode of Administration: Oral
      • Pharmacodynamics:
        • Short term ↑ in levels of serotonin, norepinephrine
        • Antidepressant effects
      • ADRs:
        • Orthostatic hypotension
        • Hypertensive crisis (Exces CNS stimulation)
        • Tremors
        • Excitement
        • Insomnia
        • Overdose
        • Convulsions
        • Headaches
        • Chest pain
        • Nausea
        • Vomiting
        • Sweating
        • Tachycardia
        • Stroke
      • Interactions:
        • TCAs
        • Serotonin syndrome (with SSRIs)
        • Antihistamines
        • Opioids
        • Tyramine
    • Bupropion
      • Mechanism: Inhibit reuptake of dopamine and norepinephrine
      • Pharmacodynamics:
        • Antidepressant effects
      • ADRs:
        • ↑ Doses = Seizures
      • Interactions:
        • Potential for abuse
    • Reboxetine
      • Mechanism: Inhibits reuptake of norepinephrine
      • Pharmacodynamics:
        • Antidepressant effects
    • Atomoxetine
      • Mechanism: Inhibits reuptake of norepinephrine
      • Pharmacodynamics:
        • Improves attention deficit hyperactivity disorder (ADHD)
    • St. John’s Wort
      • Mechanism: Inhibits reuptake of serotonin, dopamine norepinephrine, GABA, glutamate
      • Pharmacodynamics:
        • Antidepressant effects
        • Anxiolytic effects
    • Mirtazapine
      • Mechanism: Alpha2-adrenergic antagonist and serotonin 5HT1 antag
      • Pharmacodynamics:
        • Antidepressant effects

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