Pharmacology: Autonomic Nervous System - Sympathetic Nervous System

These flashcards cover critical concepts regarding the sympathetic nervous system, adrenergic drugs, their mechanisms, effects, and clinical applications relevant for Pharmacology students.

What neurotransmitters are associated with the Sympathetic Nervous System?

Norepinephrine and Epinephrine.

What is the primary function of the Sympathetic Nervous System?

Responsible for the 'fight or flight' response.

What are the types of sympathetic drugs categorized by their action?

Direct-acting, indirect-acting, and mixed-acting sympathetic drugs.

What receptors are involved in the Sympathetic Nervous System?

Alpha, Beta, and Dopamine receptors.

Name a common property exhibited by catecholamines.

Contains a catechol nucleus.

Which enzyme catalyzes the conversion of Tyrosine to DOPA?

Tyrosine hydroxylase.

What is the fate of Norepinephrine in the synaptic cleft?

Biosynthesis, release, binding to receptors, metabolism, and reuptake.

What is the main role of MAO and COMT in neurotransmitter metabolism?

They are responsible for the metabolism of catecholamines.

Where is Norepinephrine synthesized?

Inside the nerve axon and in the adrenal medulla.

What does α1 receptor stimulation result in?

Vasoconstriction and smooth muscle contraction.

What type of receptors are catecholamine receptors?

G-protein linked receptors.

What are sympathomimetic agents?

Drugs that mimic the effects of epinephrine or norepinephrine.

List examples of direct-acting sympathomimetics.

Epinephrine, Norepinephrine, Dopamine, Isoproterenol.

What mechanism do indirect-acting sympathomimetics utilize?

They increase the release of catecholamines in the synaptic cleft.

Name a commonly used selective β2 agonist for asthma management.

Salbutamol.

What is the mechanism of action of Clonidine?

Stimulates alpha-2 receptors to decrease sympathetic outflow.

What class of drugs is used for management of hypertension during pregnancy?

Methyldopa.

Which receptor is primarily stimulated by dopamine at low doses?

D1 receptor.

What is the effect of β1 receptor stimulation in the heart?

Increased heart rate and contractility.

Which type of adrenergic blocker is Prazosin?

Alpha-1 selective adrenergic blocker.

What is the action of non-selective beta blockers like Propranolol?

They block both β-1 and β-2 receptors.

What are common adverse effects of non-selective beta blockers?

Bronchospasm and decreased exercise tolerance.

What serious condition can arise from the use of MAOI and Tyramine together?

Hypertensive crisis.

What effect can High doses of β2 agonists have?

Tachycardia.

What type of response does an α2 receptor stimulation cause?

Negative feedback on norepinephrine synthesis and release.

What is significant about the structure of a catecholamine?

It contains a catechol nucleus and a beta-hydroxy group.

When should α1 agonists be used with caution?

In patients with hypertension due to potential for exacerbating symptoms.

What is the main clinical use of Isoproterenol?

Managing bronchial asthma and acute heart failure.

Which adrenergic agonist is often used as a tocolytic agent?

Terbutaline.

What is a common side effect of β2 agonists used in asthma therapy?

Tremors.

What is the primary effect of α1 agonists used as nasal decongestants?

Vasoconstriction in nasal blood vessels.

What does the term 'tachyphylaxis' refer to?

Rapid tolerance to the effects of a drug.

What is the primary class of drugs used to treat pheochromocytoma?

Alpha-adrenergic blockers.

What is the action mechanism of sympatholytics?

They bind to adrenoceptors and block their activation.

What condition may result in systemic hypertension due to discontrol of sympathetic release?

Pheochromocytoma.

What is the first dose effect seen with α1 blockers like Prazosin?

First dose syncope.

What is a significant side effect of Clonidine?

Sedation.

How are beta blockers classified based on receptor selectivity?

Selective (β1) and non-selective (β1 & β2).

What common clinical conditions are treated with α-1 blockers?

Benign prostatic hyperplasia and hypertension.

What is a major concern when using Discontinuing β blockers?

Withdrawal syndrome may occur.

What type of effect do α1 selective antagonists have on blood pressure?

They decrease blood pressure by blocking vasoconstriction.

What is the therapeutic effect of α2 adrenergic agonists on hypertension?

They reduce vascular resistance and lower blood pressure.

What is the clinical use of Dobutamine in cardiac care?

Used for cardiac stress testing and management of acute heart failure.

What does the term 'sympatholytic' specifically refer to?

Agents that inhibit sympathetic nervous system activity.

Which receptors does Carvedilol antagonize?

Both alpha and beta adrenergic receptors.

What are the potential adverse effects of β blockers regarding metabolic activity?

Altered lipid metabolism and potential weight gain.

What are adverse effects of Methyldopa?

Sedation and hepatotoxicity.

What is the highest risk side effect associated with amphetamines?

Potential for cardiac arrhythmias.

How do indirect-acting drugs differ from direct-acting agonists?

Indirect-acting drugs increase catecholamine concentration rather than bind directly.

What condition is treated with the use of antagonists like Phentolamine?

Erectile dysfunction.

Define the action of β-blockers on heart rate.

They decrease heart rate and cardiac output.

What is the significance of the terminal amino group's structure in sympathomimetic agents?

It alters their specific receptor selectivity and efficacy.

What action does Epinephrine have on a patient's blood vessels?

Vasoconstriction and increased cardiac output.

What can excessive use of nasal decongestants lead to?

Rhinitis medicamentosa.

What is the activity of Tamsulosin in the body?

It selectively blocks α1 receptors in the prostate.

What is a common clinical application of Dopamine at low doses?

Renal vasodilation and increased glomerular filtration rate.

What type of transport is involved in the reuptake of Norepinephrine?

NET (Norepinephrine transporter) facilitates reuptake.

How does Ephedrine differ from catecholamines in terms of administration?

Ephedrine is orally active, while catecholamines typically are not.

Which adrenergic antagonist is irreversibly acting?

Phenoxybenzamine.

Why might a patient be at risk for rebound hypertension after discontinuing Clonidine?

Due to sudden withdrawal leading to exaggerated sympathetic activity.

What treatment option is indicated for postural hypotension?

Midodrine, an α1 agonist.

What are the receptors affected by dopamine in the brain?

D2-like receptors, which inhibit cAMP.

What changes in blood pressure can result from α1 antagonist use?

Hypotension due to reduced vascular resistance.

What is an important pharmacokinetic consideration of catecholamines?

They undergo extensive first-pass metabolism.

What is the common mechanism of action of β2 agonist therapy in asthma?

Relaxation of bronchial smooth muscle leading to bronchodilation.

What is a known drug interaction concern with indirect-acting sympathomimetics like Tyramine?

Hypertensive episodes with MAO inhibitors.

What adverse effect can Clonidine induce when used for hypertension?

Sedation and potential for rebound hypertension.

Which beta blocker is associated with a high incidence of CNS side effects?

Propranolol.

What tests may show high levels of Norepinephrine in conditions like pheochromocytoma?

VMA assay in serum or urine.

What can happen to a patient's heart response in the presence of β blockers during hypoglycemia?

Symptoms of hypoglycemia may be masked.