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Cutaneous blood flow and local sweating after systemic atropine administration
1U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760-5007.
Pflugers Archiv : European Journal of Physiology
|November 1, 1987
Summary
Systemic atropine enhances cutaneous vasodilation during exercise, increasing blood flow to the skin. This response helps regulate body temperature by improving heat loss, even with elevated skin temperature.
Area of Science:
- Physiology
- Thermoregulation
- Pharmacology
Background:
- Localized cutaneous vasodilation, or flush, is a known response to systemic atropine.
- Understanding the impact of atropine on heat loss mechanisms is crucial for physiological studies.
Purpose of the Study:
- To investigate the effect of systemic atropine on cutaneous blood flow and vasodilation during exercise.
- To determine if atropine alters the relationship between core temperature and skin blood flow.
Main Methods:
- Four male subjects exercised at 55% VO2 peak in controlled environmental conditions (Ta = 30°C, Tdp = 7°C).
- Measurements included esophageal temperature (Tes), arm sweating (ms), and forearm skin blood flow (FBF) via venous occlusion plethysmography.
- Experiments were conducted with and without atropine administration (0.025 mg/kg, IM).
Main Results:
- Atropine significantly increased the sensitivity of forearm skin blood flow (FBF) to esophageal temperature (Tes) by 85% (p < 0.01).
- The onset threshold for sweating was elevated by 0.3°C (p < 0.05) with atropine, but sweating sensitivity remained unchanged.
- Higher skin temperatures (Tsk) were observed in atropine experiments after 15 minutes of exercise.
Conclusions:
- Systemic atropine promotes increased cutaneous vasodilation at a given core temperature, facilitating enhanced dry heat loss.
- The vasodilation response to atropine appears to be mediated by both central and local mechanisms, possibly involving vasoactive substances.