Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans. Export

@article{citeulike:2587347, abstract = {1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals. (Citado por 30)}, address = {Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, TX 752315, USA.}, author = {Wilson, T. E. and Cui, J. and Crandall, C. G.}, citeulike-article-id = {2587347}, citeulike-linkout-0 = {http://view.ncbi.nlm.nih.gov/pubmed/11600694}, citeulike-linkout-1 = {http://www.hubmed.org/display.cgi?uids=11600694}, day = {15}, issn = {0022-3751}, journal = {J Physiol}, keywords = {autonomic\_ns, baroreflex, electrodermal, ssr, sudomotor\_function}, month = {October}, number = {Pt 2}, pages = {615--623}, posted-at = {2008-03-25 18:14:24}, priority = {2}, title = {Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/11600694}, volume = {536}, year = {2001} }

TY - JOUR ID - citeulike:2587347 L3 - citeulike-article-id:2587347 N2 - 1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals. (Citado por 30) IS - Pt 2 JF - J Physiol SN - 0022-3751 AD - Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas, TX 752315, USA. EP - 623 TI - Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans. VL - 536 SP - 615 KW - autonomic_ns KW - baroreflex KW - electrodermal KW - ssr KW - sudomotor_function AU - Wilson, TE AU - Cui, J AU - Crandall, CG PY - 2001/10/15/ UR - http://view.ncbi.nlm.nih.gov/pubmed/11600694 ER -