Adenosine receptor activation influences postexercise skin blood flow (1106.20)

Abstract

Adenosine receptor activation influences postexercise skin blood flow R. N. McGinn, N. Fujii, G. P. Kenny Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, K1N 6N5 Studies show that postexercise skin blood flow (SkBF) is reduced despite persistent hyperthermia. We have ascribed this to altered active vasodilation rather than adrenergic vasoconstriction (Kenny, Front Bio 15:259 2010). However, recent work shows that adenosine receptors mediates the decrease in SkBF following passive heat stress (Swift et al, Exp Phys, Epub 2013), thus it is plausible that adenosine receptors may also modulate postexercise SkBF. Eight males cycled for 15 min (85% VO2max) and then rested for 60 min at 25°C. Four microdialysis probes were inserted in the forearm and infused with: a) Ringer’s Lactate (CON); b) L‐NAME (nitric oxide synthase inhibitor); c) bretylium tosylate (BT; sympathetic nerve transmission inhibitor) or d) theophylline (THEO; adenosine receptor inhibitor). Cutaneous vascular conductance (CVC) was calculated as SkBF divided by mean arterial pressure. End‐exercise CVC was similar at all sites except L‐NAME (18% lower, P<0.01). CVC returned to resting levels after 20 min of recovery in CON (P=0.11). Compared with CON, CVC was reduced at L‐NAME at 10 min of recovery (P=0.03) and was increased at BT for the first 30 min of recovery (P<0.05). However, THEO was elevated throughout recovery (P蠄0.01) compared to CON. We show recovery SkBF to be modulated by nitric oxide (10 min) and adrenergic vasoconstriction (30 min), but adenosine receptors exerts a more prolonged effect (60 min).Abstract body: 1216/1220 characters Total: 1464/1720 charactersGrant Funding Source: Supported by: Natural Sciences and Engineering Research Council of Canada