Description : Down regulation of receptors can occur as a consequence of: A. Continuous use of agonists B. Continuous use of antagonists C. Chronic use of CNS depressants D. Denervation
Last Answer : A. Continuous use of agonists
Description : Receptors perform the following function/functions: A. Ligand recognition B. Signal transduction C. Both ligand recognition and signal transduction D. Disposal of agonists and antagonists
Last Answer : C. Both ligand recognition and signal transduction
Description : The following statement is not true of log dose-response curve: A. It is almost linear except at the ends B. It is a rectangular hyperbola C. It facilitates comparison of different agonists D. It can help in discriminating between competitive and noncompetitive antagonists
Last Answer : B. It is a rectangular hyperbola
Description : What is true in relation to drug receptors: A. All drugs act through specific receptors B. All drug receptors are located on the surface of the target cells C. Agonists induce a conformational change in the receptor D. Partial agonists have low affinity for the receptor
Last Answer : C. Agonists induce a conformational change in the receptoR
Last Answer : C. Agonists induce a conformational change in the receptor
Description : Agonist induced autophosphorylation, internalization and down regulation is a distinctive feature of: A. G-protein coupled receptors B. Intrinsic ion channel containing receptors C. Tyrosine protein kinase receptors D. Receptors regulating gene expression
Last Answer : C. Tyrosine protein kinase receptors
Description : Which of the following is not the basis for subclassifying β adrenergic receptors into β1 and β2 : A. Selectivity of agonists B. Selectivity of antagonists C. Transducer pathway of response effectuation D. Organ selective location
Last Answer : C. Transducer pathway of response effectuation
Description : Which of the following is not the basis for subclassifying β adrenergic receptors into β 1 and β 2: A. Selectivity of agonists B. Selectivity of antagonists C. Transducer pathway of response effectuation D. Organ selective location
Description : The following is not a feature of competitive antagonists: A. Chemical resemblance with the agonist B. Parallel rightward shift of the agonist log doseresponse curve C. Suppression of maximal agonist response D. Apparent reduction in agonist affinity for the receptor
Last Answer : C. Suppression of maximal agonist response
Description : Receptor agonists possess: A. Affinity but no intrinsic activity B. Intrinsic activity but no affinity C. Affinity and intrinsic activity with a + sign D. Affinity and intrinsic activity with a – sign
Last Answer : C. Affinity and intrinsic activity with a + sign
Description : Currently, the first choice drug for open angle glaucoma is: A. Miotic eye drops B. Ocular α2 adrenergic agonists C. Ocular prostaglandin analogues D. Ocular β adrenergic blockers
Last Answer : D. Ocular β adrenergic blockers
Description : Agonists affect the receptor molecule in the following manner: A. Alter its amino acid sequence B. Denature the receptor protein C. Alter its folding or alignment of subunits D. Induce covalent bond formation
Last Answer : C. Alter its folding or alignment of subunits
Description : The following statement is not correct for uremic patients: A. Attainment of steady-state plasma concentration of drugs eliminated through the kidney is hastened B. Pethidine can cause seizures C. Diazepam produces exaggerated CNS depression D. Tetracyclines further raise blood urea level
Last Answer : A. Attainment of steady-state plasma concentration of drugs eliminated through the kidney is hastened
Description : Out of two anticholinesterases, drug X' is a tertiary amine while drug Y' is a quarternary ammonium compound. Then: A. Drug X' is likely to be more potent than Y' B. Drug X' will be more ... a miotic C. Drug Y' will be completely metabolized in the body D. Drug Y' will produce CNS effects
Last Answer : B. Drug ‘X’ will be more suitable to be used as a miotic
Description : Denervation super-sensitivity includes (a) Proliferation of receptors (b) Loss of mechanism for transmitter removal (c) Increased post-junctional responsiveness (d) All of the above
Last Answer : Ans: D
Description : The bladder trigone and prostatic muscles are relaxed by: A. Adrenergic α1 agonists B. Adrenergic α1 antagonists C. Adrenergic α2 agonists D. Adrenergic α2 antagonists
Last Answer : B. Adrenergic α1 antagonists
Description : Leukotriene antagonists are used in bronchial asthma: A. For terminating acute attacks B. As monotherapy in place of β2 agonists C. As adjuvants to β2 agonists for avoiding corticosteroids D. As nebulized powder in refractory cases
Last Answer : C. As adjuvants to β2 agonists for avoiding corticosteroids
Description : An 'orphan drug' is: A. A very cheap drug B. A drug which has no therapeutic use C. A drug needed for treatment or prevention of a rare disease D. A drug which acts on Orphanin receptors
Last Answer : C. A drug needed for treatment or prevention of a rare disease
Description : The antagonism between adrenaline and histamine is called ‘physiological antagonism’ because: A. Both are physiologically present in the body B. They act on physiological receptors C. Both affect many physiological processes D. They have opposite physiological effects
Last Answer : D. They have opposite physiological effects
Description : Study of drug-receptor interaction has now shown that: A. Maximal response occurs only when all receptors are occupied by the drug B. Drugs exert an all or none' action on a ... lock and key' structural features D. Properties of affinity' and intrinsic activity' are independently variable
Last Answer : D. Properties of ‘affinity’ and ‘intrinsic activity’ are independently variable
Description : Drugs acting through receptors exhibit the following features except: A. Structural specificity B. High potency C. Competitive antagonism D. Dependence of action on lipophilicity
Last Answer : D. Dependence of action on lipophilicity
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 : 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 : 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 : 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 cardiac muscarinic receptors: A. Are of the M1 subtype B. Are of the M2 subtype C. Are selectively blocked by pirenzepine D. Function through the PIP2 → IP3/DAG pathway
Last Answer : B. Are of the M2 subtype
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 : Adverse consequences may follow sudden discontinuation of the following drug after chronic intake: A. Cocaine B. Cannabis C. Clonidine D. All of the above
Last Answer : C. Clonidine
Description : Reflex bronchoconstriction is most likely to occur with the following form of inhaled antiasthma medication: A. Metered dose spray of drug in solution B. Dry powder rotacap C. Nebuliser D. Nebuliser with spacer
Last Answer : B. Dry powder rotacap
Description : Bioavailability differences among oral formulations of a drug are most likely to occur if the drug: A. Is freely water soluble B. Is completely absorbed C. Is incompletely absorbed D. Undergoes little first-pass metabolism
Last Answer : C. Is incompletely absorbed
Description : Afferent nerve fibres carry impulses from (a) effector organs to CNS (b) receptors to CNS (c) CNS to receptors (d) CNS to muscles.
Last Answer : (b) receptors to CNS
Description : In comparison to inhaled β 2 adrenergic agonists, the inhaled anticholinergics: A. Are more effective in bronchial asthma B. Are better suited for control of an acute attack of asthma C. Produce slower response in bronchial asthma D. Produce little benefit in chronic obstructive lung disease
Last Answer : C. Produce slower response in bronchial asthma
Description : Continuous exposure of ctecholaminesensitive cells and tissues to adrenergic agonists causes a progressive diminition in their capacity to respond, this phenomenon is called as (a) Refractoriness (b) Desensitization (c) Tachyphylaxis (d) All of the above
Description : Down regulation is (A) Increased destruction of a hormone (B) Feed back inhibition of hormone secretion (C) Decreased concentration of a hormone in blood (D) Decrease in number of receptors for a hormone
Last Answer : Answer : D
Description : The only correct statement about hormone receptors is (A) Receptors for protein hormones are present in cytosol (B) Receptors for steroid hormones are membrane bound (C) Hormone-receptor binding is irreversible (D) Receptors can undergo down regulation and up regulatoin
Description : Sulfonylurea hypoglycaemics act by: A. Reducing intestinal absorption of glucose B. Increasing insulin secretion from pancreas C. Reversing down-regulation of insulin receptors D. Both ‘B’ and ‘C’ are correct
Last Answer : D. Both ‘B’ and ‘C’ are correct
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