dxtxpx
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Effects of Ca+2 channel blockers on Vascular Smooth Muscle:
a) Large effect of Ca+2 channel blockers on receptor-operated channels or on release of Ca+2 from SR
b) Vascular selectivity is seen with the Ca+2 channel blockers
c) increase cardiac afterload
d) Decrease cardiac preload
e) Specific dihydropyridines may exhibit greater potencies in some vascular beds
f) Specific effect tracheal smooth muscle
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| asmi
Forum Hero
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b..vascular selectivity
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| dxtxpx
Forum Guru
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Yes b and e are both correct
L-type Ca++ channel blockers inhibit L-type voltage-dependent Ca++ channels
T-type Ca++ channel blockers inhibit T-type voltage-dependent Ca++ channels
Little or no effect of Ca++ channel blockers on receptor-operated channels or on release of Ca++ from SR
"Vascular selectivity" is seen with the Ca++ channel blockers
Decreased intracellular Ca++ in arterial smooth muscle results in relaxation (vasodilatation) -> decreased cardiac afterload (aortic pressure)
Little or no effect of Ca++-channel blockers on venous beds -> no effect on cardiac preload (ventricular filling pressure)
Specific dihydropyridines may exhibit greater potencies in some vascular beds (e.g.- nimodipine more selective for cerebral blood vessels, nicardipine for coronary vessels) Little or no effect on nonvascular smooth muscle (e.g. -tracheal smooth muscle)
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