title: Relationship of blood pressure to the responsiveness of an isolated human artery to selected agonists and to electrical stimulation.
abstract: Intrinsic vascular responsiveness to norepinephrine, transmural electrical stimulation, 5-hydroxy-tryptamine, and vasopressin was studied in isolated helical cut strips of cystic artery (downstream branch of hepatic artery) from 120 subjects and related to blood pressure. Blood pressure, thickness of the tunica media, and passive elastic properties of arterial strips were each significantly correlated with age. With the exception of blood pressure in the female subjects, it is doubtful that these relationships are of major biologic significance. Nevertheless, in subgroup formation, care was taken to control for age. Hypertension was arbitrarily defined in three different ways as: (a) two diastolic pressure measurements greater than or equal to 90 mm Hg (HT90); (b) two diastolic pressure measurements greater than or equal to 95 mm Hg (HT95); or (c) treatment for hypertension instituted by a physician 6 months to 2 years after arteries were studied (HTQ). In arteries of hypertensive female subjects, responsiveness to norepinephrine (and possibly to 5-hydroxytryptamine) was increased significantly over the first half of the dose-response curve, particularly in the arteries of HT95 and HTQ subjects. Responses to transmural electrical stimulation and vasopressin were not consistently different. Such differences were not seen in arteries of male subjects where, if anything, responsiveness to norepinephrine (but not 5-hydroxytryptamine) was decreased. The present observations were made in the absence of any substantive difference in arterial dimensions (e.g., cross-section area) or in the maximal response to norepinephrine. The data support the notion that, at least for female subjects, alteration in intrinsic vascular responsiveness may play a role in the pathogenesis of human essential hypertension.
mesh_terms: D000328:Adult; D000367:Age Factors; D001158:Arteries / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects*; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008236:Lypressin / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology; D012737:Sex Factors
chemical_list: D012701:Serotonin; D008236:Lypressin