Autonomic neuroscience : basic & clinical
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Comparative Study
Effect of whole-body and local heating on cutaneous vasoconstrictor responses in humans.
Animal studies suggest that alpha-adrenergic-mediated vasoconstriction is compromised during whole-body heating. The purpose of this study was to identify whether whole-body heating and/or local surface heating reduce cutaneous alpha-adrenergic vasoconstrictor responsiveness in human skin. Protocol I: Six subjects were exposed to neutral skin temperature (i.e., 34 degrees C), whole-body heating, and local heating of forearm skin to increase skin blood flow to the same relative magnitude as that observed during whole-body heating. ⋯ Statistical analyses revealed that the EC50 for 37,40 and 42 degrees C were significantly greater than the EC50 for 34 degrees C. These results indicate that even during administration of high concentrations of NE, alpha-adrenergic vasoconstriction does not fully compensate for local heating and whole-body heating induced vasodilatation in young, healthy subjects. Moreover, these data suggest that elevated local temperatures, above 37 degrees C, and whole-body heating similarly attenuate cutaneous alpha-adrenergic vasoconstriction responsiveness.