title: Alpha-adrenergic receptors in human blood vessels.
abstract: The evidence for the presence of postjunctional alpha 1- and alpha 2-adrenoceptor subtypes in human blood vessels is reviewed. Experiments in healthy subjects are described that show that alpha 1- as well as alpha 2-adrenoceptor mediated vasoconstriction contribute to vascular smooth muscle tone and that adrenaline and noradrenaline have similar affinities for each subtype. In addition, evidence is presented for a preferential intrajunctional location of alpha 1-adrenoceptors and a preferential extrajunctional location of alpha 2-adrenoceptors in human blood vessels. It is concluded that at present postjunctional alpha-adrenoceptors in human blood vessels can be classified as alpha 1 and alpha 2. Despite the fact that both subtypes mediate vasoconstriction, these receptors are likely to subserve different physiological functions.
authors.forename: P
authors.initials: P
authors.lastname: van Brummelen
authors.forename: K
authors.initials: K
authors.lastname: Jie
authors.forename: P A
authors.initials: PA
authors.lastname: van Zwieten
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D001808:Blood Vessels / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism; D006801:Humans; D009119:Muscle Contraction / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D012039:Regional Blood Flow / Q000187:drug effects; D014439:Tyramine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D002395:Catecholamines; D011942:Receptors, Adrenergic, alpha; D009638:Norepinephrine; D014439:Tyramine