1. Histamine exerts the following actions except:
A. Dilatation of large blood vessels
B. Dilatation of small blood vessels
C. Stimulation of isolated guineapig heart
D. Itching
Answer: [ D ]
2. Fall in blood pressure caused by larger doses of histamine is blocked by:
A. H1 antihistaminics alone
B. H2 antagonists alone
C. Combination of H1 and H2 antagonists
D. None of the above
Answer: [ D ]
3. The following statement about histamine is not correct:
A. It is the sole mediator of immediate hypersensitivity reaction
B. It plays no role in delayed hypersensitivity reaction
C. It serves as a neurotransmitter in the brain
D. All types of histamine receptors are G protein coupled receptors
Answer: [ D ]
4. Histamine is involved as a mediator in the following pathological condition:
A. Delayed hypersensitivity reaction
B. Inflammation
C. Carcinoid syndrome
D. Variant angina
Answer: [ D ]
8. The drug that can directly release histamine from mast cells without involving antigen-antibody reaction is:
A. Aspirin
B. Procaine
C. Morphine
D. Sulfadiazine
Answer: [ D ]
9. Autacoids differ from hormones in that:
A. Autacoids are involved only in the causation of pathological states
B. Autacoids do not have a specific cell/tissue of origin
C. Autacoids generally act locally at the site of generation and release
D. Both ‘B’ and ‘C’ are correct
Answer: [ D ]
10. Which of the following is a selective H1 receptor agonist:
A. 4-methyl histamine
B. Impromidine
C. 2-Thiazolyl ethylamine
D. Chlorpheniramine
Answer: [ C ]
10. The action of histamine that is not mediated through H1 receptors is:
A. Release of EDRF from vascular endothelium resulting in vasodilatation
B. Direct action on vascular smooth muscle causing vasodilatation
C. Bronchoconstriction
D. Release of catecholamines from adrenal medulla
Answer: [ B ]