Intradermal administration of ATP does not mitigate tyramine-stimulated vasoconstriction in human skin

American Journal of Physiology - Regulatory Integrative and Comparative Physiology - Tập 298 Số 5 - Trang R1417-R1420 - 2010
Jonathan E. Wingo1,2,3, R. Matthew Brothers1,3, Juan Del Coso3, Craig G. Crandall1,3
1Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas; and
2Department of Kinesiology, University of Alabama, Tuscaloosa, Alabama
3Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas

Tóm tắt

Cutaneous vasodilation associated with whole-body heat stress occurs via withdrawal of adrenergic vasoconstriction and engagement of cholinergic “active” vasodilation, the latter of which attenuates cutaneous vasoconstrictor responsiveness. However, the precise neurotransmitter(s) responsible for this sympatholytic-like effect remain unknown. In skeletal muscle, ATP inhibits adrenergically mediated vasoconstriction. ATP also may be responsible for attenuating cutaneous vasoconstriction since it is coreleased from cholinergic neurons. The effect of ATP on cutaneous vasoconstrictor responsiveness, however, has not been investigated. Accordingly, this study tested the hypothesis that ATP inhibits adrenergically mediated cutaneous vasoconstriction. To accomplish this objective, four microdialysis probes were inserted in dorsal forearm skin of 11 healthy individuals (mean ± SD; 35 ± 11 years). Local temperature at each site was clamped at 34°C throughout the protocol. Skin blood flow was indexed by laser-Doppler flowmetry and was used to calculate cutaneous vascular conductance (CVC; laser-Doppler-derived flux/mean arterial pressure), which was normalized to peak CVC achieved with sodium nitroprusside infusion combined with local skin heating to ∼42°C. Two membranes were perfused with 30 mM ATP, while the other two membranes were flow matched via administration of 2.8 mM adenosine to serve as control sites. After achieving stable baselines, 1×10−4 M tyramine was administered at all sites, while ATP and adenosine continued to be infused at their respective sites. ATP and adenosine infusion increased CVC from baseline by 35 ± 26% CVCpeak units and by 36 ± 15% CVCpeak units, respectively ( P = 0.75). Tyramine decreased CVC similarly (by about one-third) at all sites ( P < 0.001 for main effect and P = 0.32 for interaction). These findings indicate that unlike in skeletal muscle, ATP does not attenuate tyramine-stimulated vasoconstriction in human skin.

Từ khóa


Tài liệu tham khảo

10.1016/j.fertnstert.2005.09.024

10.1113/expphysiol.2008.043620

10.4065/78.5.603

10.1113/jphysiol.2003.049940

10.1042/bj1400001

10.1113/jphysiol.1954.sp005182

10.1113/jphysiol.2008.160358

Johnson JM, 1996, Handbook of Physiology, 215

10.1113/jphysiol.2004.071993

10.1152/japplphysiol.01071.2005

10.1161/01.RES.66.5.1420

10.1161/01.RES.77.6.1222

10.1113/jphysiol.2008.154252

10.1152/japplphysiol.01181.2006

10.1152/ajpregu.00710.2005

10.1161/01.HYP.22.4.577

10.1152/japplphysiol.00638.2009

10.1016/0014-5793(87)81518-1

Roddie IC, 2003, J Physiol (Lond), 548, 336

10.1161/01.CIR.90.4.1891

10.1113/jphysiol.2004.063107

10.1113/jphysiol.2008.155432

10.1113/jphysiol.2006.112649

10.1113/jphysiol.2007.144030

10.1152/japplphysiol.91017.2008

10.1152/jappl.1984.57.6.1878

10.1172/JCI119448

10.1113/jphysiol.2001.014431

10.1016/0306-4522(94)90223-2

10.1113/jphysiol.2002.035931

10.1152/japplphysiol.00500.2005

10.1016/S1566-0702(02)00046-2

10.1152/japplphysiol.00067.2002

10.1152/japplphysiol.91249.2008

10.1113/jphysiol.2004.071779

10.1016/0306-4522(78)90035-0

Thông tin
Thông tin xuất bản

American Journal of Physiology - Regulatory Integrative and Comparative Physiology

Tập 298 Số 5

R1417-R1420

Thông tin tác giả