Peripheral alpha 1- and alpha 2-adrenoreceptor mechanisms in blood pressure control.
Peripheral alpha-adrenoreceptors can be characterized as alpha 1 or alpha 2, depending on their affinity for agonists and antagonists. Alpha 2-adrenoreceptors, probably located postsynaptically on smooth muscle of resistance vessels, contribute to the pressor responses to intravenously given norepinephrine. Studies with the noncompetitive alpha-adrenoreceptor antagonist phenoxybenzamine suggest that there are important differences in the regulation of the two types of receptors. The slower recovery alpha 1-adrenoreceptor binding sites and the more rapid recovery of responses suggest the presence of "spare" alpha 1- but not alpha 2-adrenoreceptors.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D001794:Blood Pressure; D003000:Clonidine / Q000494:pharmacology; D004147:Dioxins / Q000494:pharmacology; D006143:Guanabenz / Q000494:pharmacology; D019329:Idazoxan; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D010643:Phenoxybenzamine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011311:Pressoreceptors / Q000187:drug effects; D011817:Rabbits; D011941:Receptors, Adrenergic / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D013569:Synapses; D014655:Vascular Resistance
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D004147:Dioxins; D011941:Receptors, Adrenergic; D011942:Receptors, Adrenergic, alpha; D010643:Phenoxybenzamine; D006143:Guanabenz; D003000:Clonidine; D009638:Norepinephrine; D011224:Prazosin; D019329:Idazoxan; D010646:Phentolamine