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Cutaneous vasodilatation responses synchronize with sweat expulsions
1Department of Physiology, Aichi Medical University, Japan.
Summary
Cutaneous active vasodilation, or positive blood flow responses (PBR), are linked to sweating, not directly to sudomotor nerve fibers. Blockade of the peroneal nerve abolished these responses, indicating nerve involvement.
Area of Science:
- Physiology
- Neuroscience
- Dermatology
Background:
- Cutaneous active vasodilation is a physiological response to heat.
- The role of sudomotor nerve fibers in mediating this vasodilation is not fully understood.
Purpose of the Study:
- To investigate whether cutaneous active vasodilation is mediated by sudomotor nerve fibers.
Main Methods:
- Continuous recording of cutaneous blood flow (laser-Doppler flowmetry) and sweat rates (capacitance hygrometry) from the foot.
- Measurements were taken in varying ambient temperatures (22-40°C) in 11 male subjects.
- Pharmacological (atropine) and nerve blockade (peroneal nerve) interventions were employed.
Main Results:
- Positive blood flow responses (PBR) on the dorsal foot synchronized with sweat expulsion, especially during continuous sweating.
- PBR also occurred with subthreshold sweat expulsion and in thermoneutral conditions when sweating was elicited by stimuli.
- Atropine did not abolish PBR, but peroneal nerve blockade eliminated both PBR and negative blood flow responses (NBR).
Conclusions:
- Cutaneous active vasodilation (PBR) is closely associated with sweating but not directly mediated by sudomotor nerve fibers.
- The findings suggest a neural pathway involving the peroneal nerve in the regulation of both sweating and active vasodilation.
- PBR appears to be linked to the sudomotor system, but not exclusively via cholinergic sudomotor fibers.