Hormone status does not alter noradrenergic sympathetic neurotransmitter involvement during local skin warming in young human females

Abstract

Previously, we reported that norepinephrine, and not neuropeptide Y (NPY), modulates basal vascular tone and contributes to the overall vasodilator response in young human females. Female reproductive hormones have been shown to alter vascular responses to NPY. We investigated the effects of female hormone status on sympathetic neurotransmitter contribution to cutaneous vasodilation in young females. Young females voluntarily taking oral contraceptives were tested during the high‐ and low‐hormone phases. Microdialysis fibers, local heaters, and laser‐Doppler probes were placed on the forearms and treated as follows: untreated control (CT), propranolol and yohimbine (YP) to antagonize a‐ and ß‐receptors, BIBP to antagonize Y1‐receptors, and bretylium toyslate to block the presynaptic release of sympathetic neurotransmitters. Sites were heated from 33 to 42 °C. YP treatment resulted in increased basal CVC at rest (P < 0.05) and reduction of peak CVC during warming (P < 0.05) compared to CT in both high‐ and low‐hormone groups. BIBP showed no effect on CVC (P >; 0.05) during either phase. These data suggest that hormone status does not alter noradrenergic sympathetic neurotransmitter involvement during rest conditions or local warming of the skin. Supported by The University of Alabama.