Pharmacology: Adrenoceptors and Their Actions
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Questions and Answers

Which receptor type primarily affects vascular smooth muscle?

  • α1 Adrenoceptors (correct)
  • α2 Adrenoceptors
  • β1 Adrenoceptors
  • β2 Adrenoceptors
  • What is the mechanism of action for α2 Adrenoceptors?

  • Increase cAMP production
  • Decrease intracellular calcium
  • Inhibit adenylyl cyclase (correct)
  • Activate phospholipase C
  • Which target tissue is affected by α1 Adrenoceptors?

  • Neurons in the brain
  • Cardiac muscle
  • Epithelial cells in the lungs
  • Smooth muscle of the iris (correct)
  • In which tissue are α2 Adrenoceptors predominantly located?

    <p>GIT wall and presynaptic adrenergic neurons</p> Signup and view all the answers

    What is the end result of α1 Adrenoceptor activation in vascular smooth muscle?

    <p>Contraction and vasoconstriction</p> Signup and view all the answers

    Which drug is primarily used for treating Parkinson's disease?

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

    What is the primary use of Atropine in clinical practice?

    <p>To treat organophosphate poisoning</p> Signup and view all the answers

    Which of the following drugs is specifically indicated for preventing motion sickness?

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

    Which drug is used in the treatment of COPD?

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

    Which of the following drugs is used to suppress respiratory secretions prior to surgery?

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

    What occurs when norepinephrine binds to the α1 receptor?

    <p>The α1 receptor undergoes a conformational change.</p> Signup and view all the answers

    What is the state of the αq subunit of the Gq protein when inactive?

    <p>Bound to GDP.</p> Signup and view all the answers

    Which of the following best describes the role of the Gq protein in α1 adrenoreceptors?

    <p>It initiates a signaling cascade through phospholipase C.</p> Signup and view all the answers

    During the activation process of the α1 receptor, what happens after GDP is released?

    <p>GTP replaces GDP on the αq subunit.</p> Signup and view all the answers

    What is the primary neurotransmitter involved in activating α1 adrenoreceptors?

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

    What is an effect of activating phospholipase C through the α1 receptor mechanism?

    <p>Increased calcium ion concentration in the cell.</p> Signup and view all the answers

    Which structural characteristic is true for α1 adrenoreceptors?

    <p>They are embedded in the cell membrane.</p> Signup and view all the answers

    What triggers the migration of the αq-GTP complex within the cell membrane?

    <p>The binding of norepinephrine to the α1 receptor.</p> Signup and view all the answers

    What is the primary action of physostigmine?

    <p>Increase acetylcholine levels</p> Signup and view all the answers

    Which drug is NOT a common use for treating glaucoma?

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

    Which of the following is true about pralidoxime (2-PAM)?

    <p>It can reactivate inhibited AChE</p> Signup and view all the answers

    What side effects does atropine aim to prevent during anticholinesterase agent toxicity?

    <p>Increased bronchial and salivary secretion</p> Signup and view all the answers

    How long does echothiophate last in its therapeutic effect for glaucoma?

    <p>100 hours</p> Signup and view all the answers

    What is the primary function of cholinergic agonists?

    <p>To mimic the effects of acetylcholine</p> Signup and view all the answers

    Which of the following is a naturally occurring alkaloid classified as a direct-acting cholinergic agonist?

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

    Which agent is appropriate for increasing heart rate in symptomatic patients with severe bradycardia following anticholinesterase toxicity?

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

    Which cholinergic agonist is considered therapeutically useful for its muscarinic effects?

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

    What does the primary action of cholinergic antagonists involve?

    <p>Binding to and blocking cholinoceptors</p> Signup and view all the answers

    Which medication is used to reduce persistent convulsions in cases of organophosphate toxicity?

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

    What is a limitation of using cholinergic agonists in clinical practice?

    <p>Little specificity leading to limited clinical use</p> Signup and view all the answers

    Cholinoceptors can be categorized into which two main types?

    <p>Muscarinic and nicotinic</p> Signup and view all the answers

    Which statement about synthetic esters of choline is true?

    <p>They include compounds like carbachol and bethanechol</p> Signup and view all the answers

    Which cholinergic agonist is primarily associated with increasing secretions in the body?

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

    What characterizes the direct-acting cholinergic agonists when compared to acetylcholine?

    <p>They mimic acetylcholine effects with prolonged action</p> Signup and view all the answers

    Which adrenergic agonist is primarily used to increase lipolysis and has effects on the detrusor muscle of the bladder?

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

    What is the primary mechanism of action for direct-acting adrenergic agonists?

    <p>Directly activating α or β receptors</p> Signup and view all the answers

    Which adrenergic receptor subtype has the highest affinity for epinephrine compared to norepinephrine?

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

    Which of the following is a noncatecholamine adrenergic agonist?

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

    What is the role of overactivity of α2 receptors in the CNS?

    <p>Inhibit norepinephrine release</p> Signup and view all the answers

    Which type of adrenergic receptor is primarily responsible for pupillary dilation?

    <p>α1</p> Signup and view all the answers

    Which of the following best describes the metabolic pathway involving catecholamines?

    <p>Rapid inactivation by COMT and MAO</p> Signup and view all the answers

    Which of the following drugs would likely be least effective orally due to rapid inactivation?

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

    Which adrenergic agonist is primarily used as a decongestant?

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

    What effect does activation of β1 receptors have on the heart?

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

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