Neuropeptide Y not involved in cutaneous vascular control in young human females taking oral contraceptive hormones.

We previously reported that the cutaneous vasodilator response to local warming in males required noradrenaline (NA) and neuropeptide-Y (NPY). Animal work has shown no role for NPY in female vascular control. We investigated the contribution of NA and NPY in human female cutaneous vascular control. Nine female and nine male participants volunteered. To elucidate whether synthetic oestrogen and progesterone altered cutaneous vascular responses, females were tested in high-hormone (HH) and low-hormone (LH) phases of oral contraceptive pill (OCP). Skin blood flow was assessed by laser-Doppler flowmetry and expressed as cutaneous vascular conductance (CVC). Treatments were: control, combined yohimbine and propranolol (YP), BIBP-3226, and bretylium tosylate (BT). YP and BT increased basal CVC (p<0.05) relative to control sites in both HH and LH phases; though, BIBP-3226 had no effect in either phase (both p>0.05). Males basal CVC was increased at all treated sites compared to control sites (all p<0.05). YP and BT treated sites were higher in HH compared to LH (p<0.05). YP and BT treatment reduced the local warming-induced vasodilatation compared to control sites (p>0.05) in both HH and LH phases; whereas, BIBP-3226 treatment had no effect (p>0.05). In males, the vasodilatation achieved at all treated sites was reduced compared to the untreated control site (p<0.05). Data indicate that NA, not NPY, regulates basal skin blood flow and contributes to the vasodilator response to local warming in young females; however, both NA and NPY play a role in both basal and heat-induced cutaneous responses in males.