LAUSR

The venoarteriolar reflex (VAR) is a local mechanism by which vasoconstriction is mediated in response to venous congestion. This response may minimize tissue overperfusion, preventing capillary damage and edema. Post-occlusive reactive hyperaemia (PORH) is used to appraise microvascular function performed by a brief local arterial occlusion resulting in a subsequent rapid transient vasodilation. In the current study, we hypothesized that type 2 diabetes (T2D) attenuates VAR and PORH responses in forearm skin in vivo. In 11 healthy older adults (Control, 58±8 years) and 13 older adults with controlled T2D (62±10 years), cutaneous blood flow measured by laser-Doppler flowmetry was monitored following a 3-min venous occlusion of 45 mmHg that elicited the VAR, followed by a 3-min recovery period and then a 5-min arterial occlusion of 240 mmHg that induced PORH. Finally, sodium nitroprusside, a nitric oxide donor, was administered to induce maximum vasodilation. VAR and PORH variables were similar between groups. By contrast, maximal cutaneous blood flow induced by sodium nitroprusside was lower in the T2D group. Taken together, our observations indicate that T2D impairs vascular smooth muscle responsiveness to nitric oxide, but not VAR and PORH in forearm skin.