Glutamate and Its Receptors in CNS

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 (5HT_1a) agonist
• Fluoxetine - Treats depression. It is a selective serotonin reuptake inhibitor (SSRI).
• Triptans (Sumatriptan) - Treats migraine headaches. It is a 5-HT_1D 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 GABA_r 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

Explore the crucial role of L-Glutamate as the primary excitatory neurotransmitter in the central nervous system. This quiz covers glutamate synthesis, storage, and its impact on neurotransmission, including the functions of ionotropic and metabotropic receptors. Understand the implications of excess glutamate and its association with conditions like excitotoxicity.