Pharmacokinetics, Pharmacodynamics, Pharmacology of Autonomic nervous system drugs, Autocoids

31.    The following drugs undergo significant first-pass effects:

a.     propranolol.

b.    penicillin G.

c.    phenytoin.

d.    tolbutamide.

32.    State true of false:

a.     noradrenaline is formed from adrenaline by the action of phenylethanolamine N-methyltransferase.

b.     dopamine is formed from L-dopa by the action of tyrosine 3-hydrolase.

c.     p-tyrosine is formed from phenylalanine by the action of phenylalanine-4-hydroxylase.

d.     tyrosine-3-hydroxyalse forms p-tyrosine from phenylalanine.

33.    When neostigmine is given to reverse the effects of d-tubocurarine, atropine is also given to:

a.     minimize the fasciculations of skeletal muscles.

b.     block muscarinic effects of d-tubocurarine.

c.     minimize parasympathetic effects of neostigmine.

d.     minimize central effects of d-tubocurarine.

34.   Methacholine differs from acetylcholine:

a.     in its longer duration of action.

b.     is hydrolyzed by AcH esterase at a faster rate.

c.     is resistant to hydrolysis by pseudocholinesterase. 

d.     has got predominant muscarinic action.

35.    Catecholamines:

a.      contain O-dihydrobenzene.

b.      produce increase in oxygen consumption.

c.      readily crosses the blood-brain barrier.

d.      are derived from beta-phenylethylalanine.

36.    Prazosin:

a.      dilates both the arterioles and venules.

b.      is a beta-adrenoceptor antagonist.

c.      has a t1/2 of 3h.

d.      is not extensively metabolized.

37.    Prostaglandin E2:

a.      causes constipation.

b.      causes bronchoconstriction.

c.      can protect the gastric mucosal cells against damage from anti-inflammatory analgesics.

d.      desensitizes afferent nerve endings to pain stimulated by bradykinin.

38.    Prostacyclin:

a.      is converted rapidly to its stable metabolite 6-keto-PGF2

b.      found more in the vessel wall than in platelets.

c.      causes bronchoconstriction.

d.      causes potent vasoconstriction. 

39.    Propranolol:

a.      blocks actions of both endogenous and exogenous sympathomimetic amines.

b.      alkylates the receptor by forming a covalent bond.

c.      blocks both the alpha and beta receptors.

d.      acts only on receptors in the CNS.

40.    Non-catecholamine sympathomimetics are:

a.      ephedrine.

b.      dopamine.

c.      phenylephrine.

d.      noradrenaline.

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