12.1 The following eicosanoid is generated through the lipoxygenase pathway:
A. Prostaglandin E2
B. Thromboxane A2
C. Leukotriene C4
D. Prostacyclin
12.2 There are no preformed stores of the following autacoid/autacoids:
A. Prostaglandins
B. Leukotrienes
C. Angiotensin II
D. All of the above
12.3 The cyclooxygenase isoenzymes COX-1 and COX-2 differ from each other in that:
A. They catalyse different pathways in prostanoid biosynthesis
B. COX-1 is inhibited by aspirin but not COX-2
C. COX-2 is inhibited by ibuprofen but not COX-1
D. COX-1 is constitutive while COX-2 is largely inducible
12.4 Which of the following is an irreversible inhibitor of cyclooxygenase:
A. Aspirin
B. Phenylbutazone
C. Indomethacin
D. Piroxicam
12.5 The prostanoid that consistently constricts blood vessels is:
A. Prostaglandin E2
B. Prostaglandin F2α
C. Thromboxane A2
D. Prostacyclin
12.6 Dysmenorrhoea is often associated with excess production of the following autacoid by the endometrium:
A. Bradykinin
B. Prostaglandin
C. Platelet activating factor
D. 5-Hydroxytryptamine
12.7 Actions of prostaglandin E2 include the following except:
A. Fall in blood pressure
B. Bronchoconstriction
C. Uterine contraction
D. Inhibition of gastric acid secretion
12.8 The following prostanoid is a potent inducer of platelet aggregation:
A. Prostacyclin
B. Prostaglandin E2
C. Prostaglandin D2
D. Thromboxane A2
12.9 Prostaglandins play pathophysiological role in the following except:
A. Patency of ductus arteriosus
B. Regulation of renal tubular salt absorption
C. Ventricular remodeling after myocardial infarction
D. Initiation of labour
12.10 Low doses of aspirin prolong bleeding time by selectively inhibiting synthesis of the following mediator in the platelets:
A. Thromboxane A2
B. 5-Hydroxytryptamine
C. Platelet activating factor
D. Prostacyclin
12.11 Aspirin in low doses produces longlasting inhibition of platelet cyclooxygenase (COX) because:
A. Platelets contain low quantity of COX
B. Platelets cannot synthesize fresh COX molecules
C. Platelets bind aspirin with high affinity
D. Platelet COX is inducible
12.12 The early pregnancy uterus is sensitive to the following oxytocic:
A. Oxytocin
B. Methylergometrine
C. Prostaglandin F2α
D. Both ‘A’ and ‘B’ are correct
12.13 Choose the correct statement about cysteinyl leukotrienes (LT-C4/D4):
A. They produce long lasting bronchoconstriction
B. They produce sustained rise in blood pressure
C. They are responsible for attracting and sequestrating neutrophils at the site of inflammation
D. Their production is inhibited by rofecoxib
12.14 The most prominent action of leukotriene B4 is:
A. Vasodilatation
B. Uterine contraction
C. Platelet aggregation
D. Chemotaxis of neutrophils and monocytes
12.15 Montelukast blocks the action of the following autacoid:
A. Prostacyclin
B. Platelet activating factor
C. Leukotriene B4
D. Leukotriene C4/D4
12.16 Cervical priming with prostaglandin results in:
A. Facilitation of sperm movement through cervical canal
B. Increased cervical tone
C. Softening of cervix
D. Increased cervical secretions
12.17 The following drug is used for cervical priming to facilitate labour:
A. Oxytocin
B. Clomiphene
C. Progesterone
D. Prostaglandin E2
12.18 Prolonged airway hyperreactivity is characteristically
caused by:
A. Histamine
B. Prostaglandin E2
C. Platelet activating factor
D. Bradykinin
12.19 The actions of platelet activating factor include the
following except:
A. Increased capillary permeability
B. Bronchodilatation
C. Vasodilatation
D. Erosion of gastric mucosa
12.1 C 12.2 D 12.3 D 12.4 A 12.5 C 12.6 B 12.7 B 12.8 D 12.9 C 12.10 A 12.11 B 12.12 C 12.13 A 12.14 D 12.15 D 12.16 C 12.17 D 12.18 C 12.19 B