Sex-differences in cholinergic, nicotinic, and β-adrenergic cutaneous vasodilation: Roles of nitric oxide synthase, cyclooxygenase, and K channels.

Previous studies indicate that sex-related differences exist in the regulation of cutaneous vasodilation, however, the mechanisms remain unresolved. We assessed if sex-differences in young adults exist for cholinergic, nicotinic, and β-adrenergic cutaneous vasodilation with a focus on nitric oxide synthase (NOS), cyclooxygenase (COX), and K channel mechanisms. In twelve young men and thirteen young women, four intradermal forearm skin sites were perfused with the following: 1) lactated Ringer's solution (control), 2) 10 mM N-nitro-l-arginine, a non-selective NOS inhibitor, 3) 10 mM ketorolac, a non-selective COX inhibitor, or 4) 50 mM BaCl, a nonspecific K channel blocker.

Regional contributions of nitric oxide synthase to cholinergic cutaneous vasodilatation and sweating in young men.

New Findings: What is the central question of this study? We evaluated whether regional variations exist in NO-dependent cutaneous vasodilatation and sweating during cholinergic stimulation. What is the main finding and its importance? Peak cutaneous vasodilatation and sweating were greater on the torso than the forearm. Furthermore, we found that NO was an important modulator of cholinergic cutaneous vasodilatation, but not sweating, across body regions, with a greater contribution of NO to cutaneous vasodilatation in the limb compared with the torso.

Heat shock protein 90 does not contribute to cutaneous vasodilatation in older adults during heat stress.

Objectives: Heat shock protein 90 (HSP90) contributes to cutaneous vasodilatation during exercise in the heat through nitric oxide (NO) synthase (NOS)-dependent mechanisms in young adults. We hypothesized that similar responses would be observed in older middle-aged adults.

Methods: In nineteen habitually active older middle-aged (56 ± 5 years) men (n = 9) and women (n = 10), cutaneous vascular conductance (CVC) was measured at four forearm skin sites continuously treated with (a) lactated Ringers solution (Control), (b) 10 mmol/L L-NAME (NOS inhibitor), (c) 178 μmol/L geldanamycin (HSP90 inhibitor), or (d) 10 mmol/L L-NAME and 178 μmol/L geldanamycin combined.