Reflex cutaneous vasoconstriction during cold pressor test is mediated through alpha-adrenoceptors.

Abstract

The effects of the cold pressor test on the coronary circulation have been clearly defined but the effects on the peripheral vasculature are less well understood. To measure the peripheral vasomotor response during cold pressor test perfusion in the upper extremity contralateral to the cold immersion was assessed by laser Doppler flowmetry and skin-surface temperature gradients. To identify the mechanism of vasoconstriction, cold pressor test was performed before and after the administration of phentolamine, an alpha-adrenoceptor antagonist. Vasoconstriction during cold pressor test was demonstrated by both skin-surface temperature gradients and by laser Doppler flowmetry. This vasoconstrictor response was significantly attenuated by the administration of phentolamine. The results demonstrate that the cold pressor test induces an alpha-adrenoceptor mediated vasoconstriction in the peripheral vasculature.