Temperature-dependent interaction between vasoconstrictor and vasodilator mechanisms in human skin

Area of Science:

• Physiology
• Thermoregulation
• Cutaneous Vasomotor Control

Background:

• The thermoregulatory state's impact on skin blood flow is not fully understood.
• Skin blood flow regulation is crucial for maintaining body temperature homeostasis.

Purpose of the Study:

• To investigate how thermoregulatory state affects skin blood flow responses to various stimuli.
• To explore the influence of ambient temperature on cutaneous vasomotor reflexes.

Main Methods:

• 17 healthy subjects were exposed to different ambient temperatures.
• Skin blood flow was measured using laser Doppler flowmetry and photoelectrical pulse plethysmography.
• Stimuli included intraneural electrical stimulation (INS), mental stress, arousal, and deep breaths.

Main Results:

• Both INS and mental stress elicited similar skin blood flow changes.
• Warm subjects showed cutaneous vasoconstriction, while cold subjects exhibited vasodilatation.
• Arousal stimuli and deep breaths produced similar, less pronounced responses.
• Differences in responses between hands and feet suggest spatial vasomotor control.

Conclusions:

• The thermoregulatory state significantly impacts the direction and magnitude of cutaneous vasomotor reflex responses.
• Thermoregulation plays a profound role in modulating sympathetic nervous system activity affecting skin blood flow.
• Evidence suggests a spatially organized control of vasomotor responses within the peripheral circulation.