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Reflex cutaneous vasoconstriction during cold pressor test is mediated through alpha-adrenoceptors
1Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21287.
Summary
The cold pressor test causes vasoconstriction in peripheral blood vessels. This response is mediated by alpha-adrenoceptors and can be blocked by phentolamine.
Area of Science:
- Physiology
- Cardiovascular Research
- Pharmacology
Background:
- The effects of the cold pressor test (CPT) on coronary circulation are known, but its impact on peripheral vasculature remains unclear.
- Understanding peripheral vasomotor responses to CPT is crucial for assessing overall cardiovascular reactivity.
Purpose of the Study:
- To measure the peripheral vasomotor response in the upper extremity during the cold pressor test.
- To identify the specific mechanism, particularly the role of alpha-adrenoceptors, mediating vasoconstriction during CPT.
Main Methods:
- Assessed peripheral vasomotor response using laser Doppler flowmetry and skin-surface temperature gradients in the limb contralateral to cold immersion.
- Administered phentolamine, an alpha-adrenoceptor antagonist, before and during the cold pressor test to evaluate its effect on vasoconstriction.
Main Results:
- Cold pressor test induced significant vasoconstriction, confirmed by both skin-surface temperature gradients and laser Doppler flowmetry.
- Phentolamine administration significantly attenuated the vasoconstrictor response observed during the cold pressor test.
Conclusions:
- The cold pressor test elicits a vasoconstrictor response in the peripheral vasculature.
- This vasoconstriction is mediated by alpha-adrenoceptors, as demonstrated by the attenuation of the response after phentolamine administration.