Description : Tetrodotoxin blocks nerve impulse/junctional transmission by: A. Anticholinergic action B. Depleting acetylcholine C. Blocking Na+ channels D. Blocking Ca2+ channels
Last Answer : C. Blocking Na+ channels
Description : Tyramine induces release of noradrenaline from adrenergic nerve endings: A. By depolarizing the axonal membrane B. By mobilizing Ca2+ C. By a nonexocytotic process D. Only in the presence of MAO inhibitors
Last Answer : C. By a nonexocytotic process
Description : The mechanism by which neostigmine improves contraction of myasthenic muscle involves: A. Repetitive binding of the acetylcholine molecules to the same receptors at the muscle endplate B. Diffusion of ... Activation of motor end-plate receptors by neostigmine molecules themselves D. All of the above
Last Answer : D. All of the above
Description : The primary reason for preferring phentolamine as the α adrenergic blocker for performing diagnostic test for pheochromocytoma is: A. It produces rapid and short lasting α-adrenergic blockade B. It equally ... It is the most potent α blocker D. It has no additional β adrenergic blocking property
Last Answer : A. It produces rapid and short lasting α-adrenergic blockade
Description : Dantrolene sodium reduces skeletal muscle tone by: A. Reducing acetylcholine release from motor nerve endings B. Suppressing spinal polysynaptic reflexes C. Inhibiting the generation of muscle action potential D. Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre
Last Answer : D. Reducing Ca2+ release from sarcoplasmic reticulum in the muscle fibre
Description : Muscarinic cholinergic receptors: A. Are located only on parasympathetically innervated effector cells B. Mediate responses by opening an intrinsic Na+ ion channel C. Are present on vascular endothelium which has no cholinergic nerve supply D. Predominate in the autonomic ganglia
Last Answer : C. Are present on vascular endothelium which has no cholinergic nerve supply
Description : Beta adrenergic blockers lower intraocular tension by: A. Down regulating adenylyl cyclase in ciliary body through reduced activation of β2 adrenoceptors B. Constricting ciliary blood vessels ... action on trabecular meshwork D. Reducing aqueous formation unrelated to beta adrenoceptor mediation
Last Answer : A. Down regulating adenylyl cyclase in ciliary body through reduced activation of β2 adrenoceptors
Description : Choose the correct statement about drotaverine: A. It is a smooth muscle antispasmodic acting by non-anticholinergic mechanisms B. It is a papaverine congener used in peripheral vascular diseases C. It ... used to control diarrhoea D. It is a M1/M3 selective antagonist used for spastic constipation
Last Answer : A. It is a smooth muscle antispasmodic acting by non-anticholinergic mechanisms
Description : The most probable mechanism of anticonvulsant action of phenytoin is: A. Facilitation of GABAergic inhibitory transmission B. Hyperpolarization of neurones C. Interaction with Ca2+ channels to promote Ca2+ influx D. Prolongation of voltage sensitive neuronal Na+ channel inactivation
Last Answer : D. Prolongation of voltage sensitive neuronal Na+ channel inactivation
Description : Acetylcholine has no therapeutic application because: A. None of its actions are beneficial in any condition B. Its effects are transient C. It produces wide spread actions affecting many organs D. Both ‘B’ and ‘C’ are correct
Last Answer : D. Both ‘B’ and ‘C’ are correct
Description : Which of the following secretions is not stimulated by acetylcholine: A. Tear B. Bile C. Pancreatic juice D. Sweat
Last Answer : B. Bile
Description : Pseudocholinesterase differs from true cholinesterase in that: A. It does not hydrolyse acetylcholine B. It hydrolyses acetylcholine at a slower rate C. It is more susceptible to inhibition by physostigmine D. It is the only form of circulating cholinesterase
Last Answer : B. It hydrolyses acetylcholine at a slower rate
Description : The principal process which terminates the action of noradrenaline released from adrenergic nerve ending is: A. Degradation by MAO B. Methylation by COMT C. Axonal uptake D. Extraneuronal uptake
Last Answer : C. Axonal uptake
Description : The cotransmitter may serve the following function/ functions: A. Regulate the release of the primary transmitter from the nerve ending B. Alter postjunctional action of the primary transmitter C. Itself act as an alternative transmitter D. All of the above
Description : e primary mechanism by which general anaesthetics produce their action is: A. Affecting receptor operated ion channels in cerebral neurones B. Blocking voltage sensitive Na+ channels in neuronal ... activity of cerebral neurones D. Blocking production of high energy phosphates in the brain
Last Answer : A. Affecting receptor operated ion channels in cerebral neurones
Description : Select the β-adrenergic blocker that has additional α1 blocking, vasodilator and antioxidant properties: A. Carvedilol B. Celiprolol C. Acebutolol D. Metoprolol
Last Answer : A. Carvedilol
Description : The quarternary analogues of belladonna alkaloids are preferred over the natural alkaloids for antisecretory/ antispasmodic indications because: A. They have additional nicotinic receptor blocking activity B. They are ... of CNS and ocular effects D. Dose to dose they are more potent than atropine
Last Answer : C. They are devoid of CNS and ocular effects
Description : Select the β -adrenergic blocker that has additional α 1 blocking, vasodilator and antioxidant properties: A. Carvedilol B. Celiprolol C. Acebutolol D. Metoprolol
Description : The following is true of fenfluramine except: A. It lacks CNS stimulant action B. Its use has been associated with cardiac abnormalities and pulmonary hypertension C. It causes weight loss independent of reduced food intake D. It enhances serotonergic transmission in the brain
Last Answer : C. It causes weight loss independent of reduced food intake
Description : During the propagation of a nerve impulse, the action potential results from the movement of (a) K+ ions from intracellular fluid to extracellular fluid (b) Na+ ions from extracellular ... extracellular fluid to intracellular fluid (d) Na+ ions from intracellular fluid to extracellular fluid.
Last Answer : (b) Na+ ions from extracellular fluid to intracellular fluid
Description : What is true of sildenafil: A. It enhances sexual enjoyment in normal men B. It delays ejaculation C. It improves penile tumescence in men with erectile dysfunction D. It blocks cavernosal α2 adrenoceptors
Last Answer : C. It improves penile tumescence in men with erectile dysfunction
Description : A sympathomimetic amine that acts almost exclusively by releasing noradrenaline from the nerve endings is: A. Ephedrine B. Dopamine C. Isoprenaline D. Tyramine
Last Answer : D. Tyramine
Description : Metoclopramide blocks apomorphine induced vomiting, produces muscle dystonias and increases prolactin release indicates that it has: A. Anticholinergic action B. Antihistaminic action C. Anti 5-HT3 action D. Antidopaminergic action
Last Answer : D. Antidopaminergic action
Description : Amiloride inhibits K+ excretion in the distal tubules and collecting ducts by blocking: A. Electrogenic K+ channels B. Electrogenic Na+ channels C. Nonelectrogenic Na+-Cl– symport D. H+K+ATPase
Last Answer : B. Electrogenic Na+ channels
Description : The following is true of propafenone except: A. It is a weak Na+ channel blocker B. It markedly delays recovery of myocardial Na+ channels C. It has additional β-adrenergic blocking property D. It slows anterograde as well as retrograde conduction in the WPW bypass tract
Last Answer : A. It is a weak Na+ channel blocker
Description : Local anaesthetics block nerve conduction by: A. Blocking all cation channels in the neuronal membrane B. Hyperpolarizing the neuronal membrane C. Interfering with depolarization of the neuronal membrane D. Both ‘B’ and ‘C’ are correct
Last Answer : C. Interfering with depolarization of the neuronal membrane
Description : Consider the following statements: 1. Even when a nerve cell is not conducting an impulse, it is actively transporting K+ and Na+ ions in and out respectively against their concentration gradients at the expense of energy 2. As a ... is/are untrue? (a) 1 only (b) 1, 2, 4 (c) 2, 4 (d) 4 only
Last Answer : Ans:(d)
Description : A resting nerve is relatively resistant to blockade by lignocaine compared to one which is repeatedly stimulated because: A. Lignocaine penetrates resting nerve membrane poorly B. Lignocaine binds ... promotes ionization of lignocaine D. Nodes of Ranvier are inaccessible in the resting state
Last Answer : B. Lignocaine binds more avidly to the inactivated Na+ chan
Description : The positive inotropic action of digoxin takes several hours to develop because: A. Binding of digoxin to Na+K+ATPase is slow B. After Na+K+ATPase inhibition by digoxin, Ca2+ loading of myocardial ... +ATPase through modification of gene function which takes time D. Both A' and B' are correc
Last Answer : D. Both ‘A’ and ‘B’ are correct
Description : yocardial Na+ channel blockade by lignocaine has the following characteristic: A. It blocks inactivated Na+ channels more than activated channels B. It blocks activated Na+ channels more than inactivated ... Na+ channels D. It produces more prominent blockade of atrial than ventricular Na+ channels
Last Answer : A. It blocks inactivated Na+ channels more than activated channels
Description : The following is not true of quinidine: A. It blocks myocardial Na+ channels primarily in the open state B. It has no effect on myocardial K+ channels C. It produces frequency dependent blockade of myocardial Na+ channels D. It delays recovery of myocardial Na+ channels
Last Answer : B. It has no effect on myocardial K+ channels
Description : Esmolol has the following features except: A. Rapidly developing, shortlasting β adrenergic blockade B. Cardioselectivity of action C. Intrinsic sympathomimetic activity D. Suitability for intraoperative use
Last Answer : C. Intrinsic sympathomimetic activity
Description : Ephedrine is similar to adrenaline in the following feature: A. Potency B. Inability to penetrate blood-brain barrier C. Duration of action D. Producing both α and β adrenergic effects
Last Answer : D. Producing both α and β adrenergic effects
Description : The following action of adrenaline is mediated by both α and β receptors producing the same directional effect: A. Cardiac stimulation B. Intestinal relaxation C. Dilatation of pupil D. Bronchodilatation
Last Answer : B. Intestinal relaxation
Description : The following sympathomimetic amine has agonistic action on α1 + α2 + β1 + β3 adrenoceptors, but not on β2 receptors: A. Adrenaline B. Noradrenaline C. Isoprenaline D. Phenylephrine
Last Answer : B. Noradrenaline
Description : Which of the following mydriatics has the fastest and briefest action: A. Atropine B. Homatropine C. Tropicamide D. Cyclopentolate
Last Answer : C. Tropicamide
Description : Neostigmine is beneficial in cobra envenomation because: A. It binds to and inactivates cobra toxin B. It reverses coma due to cobra toxin C. It counteracts the cardio-depressant action of cobra toxin D. It antagonizes the paralysing action of cobra toxin
Last Answer : D. It antagonizes the paralysing action of cobra toxin
Description : Agonistic action on which of the following adrenergic receptors located on ciliary epithelial cells reduces aqueous secretion: A. β1 receptor B. β2 receptor C. α1 receptor D. α2 receptor
Last Answer : D. α2 receptor
Description : Edrophonium is more suitable for differentiating myasthenic crisis from cholinergic crisis because of its: A. Shorter duration of action B. Longer duration of action C. Direct action on muscle end-plate D. Selective inhibition of true cholinesterase
Last Answer : A. Shorter duration of action
Description : Pyridostigmine differs from neostigmine in that: A. It is more potent orally B. It is longer acting C. It produces less muscarinic side effects D. It does not have any direct action on NM receptors
Last Answer : B. It is longer acting
Description : Neostigmine is preferred over physostigmine for treating myasthenia gravis because: A. It is better absorbed orally B. It has longer duration of action C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate D. It penetrates blood-brain barrier
Last Answer : C. It has additional direct agonistic action on nicotinic receptors at the muscle end plate
Description : The anticholinesterase action of edrophonium is short lasting because termination of its action depends on: A. Dissociation and diffusion of the drug from the enzyme B. Hydrolysis of the drug by the enzyme C. Synthesis of fresh enzyme molecules D. A combination of the above three processes
Last Answer : A. Dissociation and diffusion of the drug from the enzyme
Description : The following action of adrenaline is not mediated by β receptors: A. Dilatation of blood vessels B. Dilatation of pupil C. Bronchodilation D. Renin release from kidney
Last Answer : B. Dilatation of pupil