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Asked by: Marusya Nilima
medical health heart and cardiovascular diseasesDoes Alpha 2 cause vasoconstriction?
The role of the alpha(2)-AR family has long been known to include presynaptic inhibition of neurotransmitter release, diminished sympathetic efferent traffic, vasodilation and vasoconstriction. This complex response is mediated by one of three subtypes which all uniquely affect blood pressure and blood flow.
Also know, how do alpha 2 receptors cause vasoconstriction?
Activation of sympathetic nerves innervating blood vessels results in smooth muscle contraction (vasoconstriction) reducing the caliber of the artery or vein. Alpha-2 adrenoceptors are present on presynaptic nerve terminals and, when activated, inhibit the release of norepinephrine.
Accordingly, how do alpha 2 agonists affect blood pressure?
Alpha 2 receptors in the brain stem and in the periphery inhibit sympathetic activity and thus lower blood pressure. Alpha 2 receptor agonists such as clonidine or guanabenz reduce central and peripheral sympathetic overflow and via peripheral presynaptic receptors may reduce peripheral neurotransmitter release.
Alpha 1 receptors are the classic postsynaptic alpha receptors and are found on vascular smooth muscle. They determine both arteriolar resistance and venous capacitance, and thus BP. Alpha 2 receptors are found both in the brain and in the periphery. In the brain stem, they modulate sympathetic outflow.