TY - JOUR
T1 - Cutaneous interstitial nitric oxide concentration does not increase during heat stress in humans
AU - Crandall, C. G.
AU - MacLean, D. A.
PY - 2001
Y1 - 2001
N2 - Inhibition of cutaneous nitric oxide (NO) synthase reduces the magnitude of cutaneous vasodilation during whole body heating in humans. However, this observation is insufficient to conclude that NO concentration increases in the skin during a heat stress. This study was designed to test the hypothesis that whole body heating increases cutaneous interstitial NO concentration. This was accomplished by placing 2 microdialysis membranes in the forearm dermal space of 12 subjects. Both membranes were perfused with lactated Ringer solutions at a rate of 2 μl/min. In both normothermia and during whole body heating via a water perfused suit, dialysate from these membranes were obtained and analyzed for NO using the chemiluminescence technique. In six of these subjects, after the heat stress, the membranes were perfused with a 1 M solution of acetylcholine to stimulate NO release. Dialysate from these trials was also assayed to quantify cutaneous interstitial NO concentration. Whole body heating increased skin temperature from 34.6 ± 0.2 to 38.8 ± 0.2°C (P < 0.05), which increased sublingual temperature (36.4 ± 0.1 to 37.6 ± 0.1°C; P < 0.05), heart rate (63 ± 5 to 93 ± 5 beats/min; P < 0.05), and skin blood flow over the membranes (21 ± 4 to 88 ± 10 perfusion units; P < 0.05). NO concentration in the dialysate did not increase significantly during of the heat stress (7.6 ± 0.7 to 8.6 ± 0.8 μM; P > 0.05). After the heat stress, administration of acetylcholine in the perfusate significantly increased skin blood flow (128 ± 6 perfusion units) relative to both normothermic and heat stress values and significantly increased NO concentration in the dialysate (15.8 ± 2.4 μM). These data suggest that whole body heating does not increase cutaneous interstitial NO concentration in forearm skin. Rather, NO may serve in a permissive role in facilitating the effects of an unknown neurotransmitter, leading to cutaneous vasodilation during a heat stress.
AB - Inhibition of cutaneous nitric oxide (NO) synthase reduces the magnitude of cutaneous vasodilation during whole body heating in humans. However, this observation is insufficient to conclude that NO concentration increases in the skin during a heat stress. This study was designed to test the hypothesis that whole body heating increases cutaneous interstitial NO concentration. This was accomplished by placing 2 microdialysis membranes in the forearm dermal space of 12 subjects. Both membranes were perfused with lactated Ringer solutions at a rate of 2 μl/min. In both normothermia and during whole body heating via a water perfused suit, dialysate from these membranes were obtained and analyzed for NO using the chemiluminescence technique. In six of these subjects, after the heat stress, the membranes were perfused with a 1 M solution of acetylcholine to stimulate NO release. Dialysate from these trials was also assayed to quantify cutaneous interstitial NO concentration. Whole body heating increased skin temperature from 34.6 ± 0.2 to 38.8 ± 0.2°C (P < 0.05), which increased sublingual temperature (36.4 ± 0.1 to 37.6 ± 0.1°C; P < 0.05), heart rate (63 ± 5 to 93 ± 5 beats/min; P < 0.05), and skin blood flow over the membranes (21 ± 4 to 88 ± 10 perfusion units; P < 0.05). NO concentration in the dialysate did not increase significantly during of the heat stress (7.6 ± 0.7 to 8.6 ± 0.8 μM; P > 0.05). After the heat stress, administration of acetylcholine in the perfusate significantly increased skin blood flow (128 ± 6 perfusion units) relative to both normothermic and heat stress values and significantly increased NO concentration in the dialysate (15.8 ± 2.4 μM). These data suggest that whole body heating does not increase cutaneous interstitial NO concentration in forearm skin. Rather, NO may serve in a permissive role in facilitating the effects of an unknown neurotransmitter, leading to cutaneous vasodilation during a heat stress.
KW - Acetylcholine
KW - Active cutaneous vasodilation
KW - Skin blood flow
KW - Thermoregulation
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U2 - 10.1152/jappl.2001.90.3.1020
DO - 10.1152/jappl.2001.90.3.1020
M3 - Article
C2 - 11181614
AN - SCOPUS:0035115050
SN - 8750-7587
VL - 90
SP - 1020
EP - 1024
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 3
ER -