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Axon reflexes in human cold exposed fingers
1The Netherlands Organisation for applied Scientific Research (TNO), Department of Work Environment, Soesterberg, The Netherlands. Daanen@tm.tno.nl
European Journal of Applied Physiology
|January 19, 2000
Summary
Cold exposure prevents axon reflexes in fingers, challenging the theory that these reflexes cause cold induced vasodilatation (CIVD). This study suggests CIVD mechanisms do not involve axon reflexes in cold-exposed hands.
Area of Science:
- Physiology
- Neuroscience
- Vascular Biology
Background:
- Cold exposure in fingers triggers cold induced vasodilatation (CIVD).
- The precise physiological mechanism underlying CIVD remains a subject of debate.
- A prominent hypothesis suggests that axon reflexes are responsible for initiating CIVD.
Purpose of the Study:
- To investigate the role of axon reflexes in the phenomenon of cold induced vasodilatation.
- To determine if axon reflexes are present in cold-exposed fingers.
Main Methods:
- Electrical stimulation was used to evoke axon reflexes in the middle fingers of human hands.
- Hands were immersed in water at two different temperatures: 5°C (cold) and 35°C (warm).
- The presence and intensity of axon reflexes were assessed under both cold and warm conditions.
Main Results:
- Axon reflexes were significantly pronounced in the middle finger of the hand immersed in warm water (35°C).
- Conversely, axon reflexes were notably absent in the middle finger of the hand immersed in cold water (5°C).
- Despite the cold exposure, electrical stimulation was perceived as painful, indicating sensory nerve function was intact.
Conclusions:
- The findings demonstrate that axon reflexes do not occur in a cold-exposed hand.
- This evidence strongly suggests that axon reflexes are unlikely to be the primary mechanism driving cold induced vasodilatation.
- Further research is needed to elucidate the actual mechanisms responsible for CIVD.