Pharma - Berto - L7 part 2

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Questions and Answers

What is the primary reason adrenaline is preferred over noradrenaline in the treatment of anaphylactic shock?

Adrenaline can stimulate both α and β receptors effectively. (correct)

Noradrenaline primarily acts on histamine receptors.

Noradrenaline is ineffective due to low blood pressure.

Adrenaline has a longer half-life than noradrenaline.

Which characteristic of adrenaline limits its effectiveness when administered orally?

It is ineffective due to CNS penetration.

It undergoes rapid oxidation and conjugation in the liver. (correct)

It is a potent bronchoconstrictor.

Its half-life is excessively long.

Which of the following statements about noradrenaline is true?

It can be used for treating asthma by dilating airways.

It stimulates β2 receptors to reduce blood flow.

It causes vasodilation at small doses.

It is suitable for treating cardiogenic shock. (correct)

What is a significant side effect of ephedrine due to its mixed action?

Increased neurotransmitter release. Signup and view all the answers

What distinguishes dopamine's action compared to norepinephrine at low concentrations?

Dopamine increases renal blood flow through vasodilation. Signup and view all the answers

Which route of administration for adrenaline provides the fastest absorption?

Intravenous. Signup and view all the answers

Why is salbutamol preferred over isoproterenol for treating asthma?

Isoproterenol has strong side effects. Signup and view all the answers

Which phenomenon explains the restlessness felt after adrenaline administration?

Cardiovascular effects lead to agitation. Signup and view all the answers

Which statement regarding the metabolism of adrenaline is correct?

It is rapidly degraded mainly by MAO. Signup and view all the answers

What is the primary role of VMAT1 and VMAT2 in relation to catecholamines?

They mediate the vesicular transport of catecholamines into synaptic vesicles. Signup and view all the answers

What impact does adrenaline have on blood glucose levels?

It increases the concentrations of glucose in the blood. Signup and view all the answers

Which drug is known to irreversibly block the activity of monoamine oxidases (MAOs)?

Iproniazide Signup and view all the answers

Which property distinguishes noradrenergic transporters from vesicular transporters?

Noradrenergic transporters can also reuptake dopamine. Signup and view all the answers

How do amphetamine and methamphetamine primarily differ from classical sympathomimetics?

They provide a non-vesicular release of catecholamines. Signup and view all the answers

What function do muscarinic receptors primarily serve in the body?

They help in the functioning of the parasympathetic system. Signup and view all the answers

Which of the following drugs blocks noradrenaline transporters (NET)?

Cocaine Signup and view all the answers

What effect does the drug reserpine have on catecholamines?

It leads to a depletion of catecholamines in synaptic vesicles. Signup and view all the answers

What distinguishes nicotinic receptors from muscarinic receptors?

Nicotinic receptors are coupled to ion channels. Signup and view all the answers

Which substance primarily competes with catecholamines in non-vesicular release?

Amphetamine Signup and view all the answers

What is a common characteristic of tricyclic antidepressants regarding net transporters?

They have higher affinity for NET than DAT. Signup and view all the answers

What is the primary role of M1 muscarinic receptors in the gastric parietal cells and CNS?

Depolarization and slow excitation Signup and view all the answers

Which of the following is NOT a consequence of sympathetic stimulation in the body?

Increased motility of the GI tract Signup and view all the answers

How do M2 and M4 muscarinic receptors primarily affect cellular responses?

By inhibiting adenylyl cyclase Signup and view all the answers

Which adrenergic agonist is primarily used for managing asthma?

Salbutamol Signup and view all the answers

Why is adrenaline the first drug of choice for anaphylactic shock over noradrenaline?

Adrenaline has a broader receptor activation profile Signup and view all the answers

Which of the following is a characteristic effect of M3 muscarinic receptors?

Increased peristalsis in the GI tract Signup and view all the answers

Clonidine is primarily used in clinical settings for which condition?

Hypertension Signup and view all the answers

What is the function of β1 adrenergic agonists, such as dobutamine?

Positive inotropic effect on the heart Signup and view all the answers

What effect does parasympathetic stimulation have on the bronchial muscles?

Contraction of bronchial muscles Signup and view all the answers

What is the primary action of phenylephrine in a clinical setting?

As a nasal decongestant Signup and view all the answers

Which of the following statements about the effects of amphetamines on the central nervous system is true?

They stimulate respiratory centers when they are depressed. Signup and view all the answers

What is a common side effect of alpha-blockers that is related to their antihypertensive action?

Retrograde ejaculation. Signup and view all the answers

What adverse effect is specifically linked to the use of beta-blockers?

Bronchoconstriction. Signup and view all the answers

Which therapeutic application would NOT typically involve sympathomimetics?

Hypertension management. Signup and view all the answers

What is a noted effect of amphetamines at high doses?

Increased serotonin release. Signup and view all the answers

Which treatment is indicated for amphetamine toxicity?

Urine acidification. Signup and view all the answers

What could be a significant consequence of prolonged use of sympathomimetics?

Drug addiction. Signup and view all the answers

Which type of beta-blocker is likely to cause less sedation due to low penetration into the blood-brain barrier?

Atenolol. Signup and view all the answers

What condition could result from excessive use of sympathomimetics?

Convulsions. Signup and view all the answers

Which of the following is NOT a common use for beta-agonists?

Anaphylactic reactions. Signup and view all the answers

Study Notes

Catecholamines

Accumulate in synaptic vesicles via VMAT1 and VMAT2 protonic pumps, which can be targeted pharmacologically.
Reserpine inhibits catecholamine vesicular transport, leading to their depletion and is used as an antihypertensive.
Amphetamines and methamphetamine are indirect sympathomimetics that promote non-vesicular catecholamine release and activate the sympathetic system.

Noradrenergic Synapse

Noradrenaline transporters (NET) are Na+/Cl- dependent and can also reuptake dopamine.
NET operates at the plasma membrane, while VMAT transports catecholamines within vesicles.
Desipramine blocks NET; cocaine and methylphenidate inhibit it too.
MAO inhibitors like iproniazid irreversibly block monoamine oxidases.

Cholinergic Synapses

Two cholinergic receptor types: muscarinic (metabotropic) and nicotinic (channel-like).
Muscarinic receptors have subtypes (M1, M2, M3, M4, M5) with distinct roles in the parasympathetic system.
M1 receptors: CNS involvement; M3 receptors: smooth muscle contractions; M2/M4 receptors: inhibition of adenylyl cyclase, inducing hyperpolarization.

Sympathetic vs. Parasympathetic Effects

Sympathetic stimulation causes pupil dilation, increased heart rate, bronchodilation, and decreased GI motility.
Parasympathetic stimulation leads to pupil constriction, bradycardia, bronchoconstriction, and increased GI secretions.

Direct Drugs: Adrenergic Agonists

Endogenous catecholamines include adrenaline, noradrenaline, and dopamine, with specific receptors and actions.
Dobutamine: preferentially targets β1 receptors; treats heart failure.
Isoproterenol: β2 agonist used for asthma treatment.
Phenylephrine: preferential α1 agonist, used as a nasal decongestant; can cross BBB, causing addiction.
Clonidine: α2 agonist, used for hypertension and migraine prophylaxis.

Clinical Uses of Adrenergic Drugs

Adrenaline: first-choice for anaphylactic shock.
Dobutamine: primary drug for congestive heart failure.
Salbutamol: selective β2 agonist for asthma relief.

Pharmacokinetics

Adrenaline is sensitive to UV light and should be administered in small doses.
Routes of administration are primarily parenteral; oral administration is ineffective due to rapid metabolism.

Endogenous Catecholamines

Adrenaline: strong stimulator of α and β receptors; used in cardiac arrest and anaphylaxis.
Noradrenaline: not used for anaphylactic shock; effective for cardiogenic shock.
Dopamine: improves renal perfusion at low doses; positive inotropic effects at higher concentrations.

Amphetamines

Indirect sympathomimetic drugs used recreationally; increase sympathetic system activity.
Can treat ADHD but have high toxicity risks including cardiovascular issues.

Therapeutic Applications of Sympathomimetics

Used for various shock types, hypotension, hypertension, cardiac arrhythmias, asthma, and certain anxiety disorders.
Risks include excessive vasoconstriction, cardiac arrhythmias, and CNS-side effects.

Adrenergic Antagonists

Alpha-blockers: used for benign prostatic hyperplasia and hypertension; may cause retrograde ejaculation.
Beta-blockers: treat hypertension, arrhythmias, and anxiety; important to monitor for bronchoconstriction, especially in asthmatics.

Conclusion

Drugs that modulate adrenergic receptors significantly impact cardiovascular and respiratory functions.
The balance of agonists and antagonists illustrates the need for selective targeting of adrenergic receptors based on therapeutic requirements.

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Description

Explore the role of catecholamines in the body, particularly their accumulation within synaptic vesicles and the effects of various pharmaceutical agents like reserpine. This quiz will delve into the mechanisms of action, including protonic pumps and sympathomimetics.