Tasaki I, Kusano K, Byrne P M
Laboratory of Cell biology, National Institute of Mental Health, Bethesda, Maryland 20892.
Biophys J. 1989 Jun;55(6):1033-40. doi: 10.1016/S0006-3495(89)82902-9.
Mechanical and thermal changes associated with a propagated nerve impulse were determined using the garfish olfactory nerve. Production of an action potential was found to be accompanied by swelling of the nerve fibers. The swelling starts nearly at the onset of the action potential and reaches its peak at the peak of the action potential. There is a decrease in the length of the fibers while an impulse travels along the fibers. The time-course of the initial heat was determined at room temperature using heat-sensors with a response-time of 2-3 ms. Positive heat production was found to start and reach its peak nearly simultaneously with the action potential. The rise in temperature of the nerve was shown to be 23 (+/- 4) mu degrees C. In the range between 10 degrees and 20 degrees C, the temperature coefficient of heat production is negative, primarily due to prolongation of the period of positive heat production at low temperatures. The amount of heat absorbed during the negative phase varies widely between 45 and 85% of the heat evolved during the positive phase. It is suggested that both mechanical and thermal changes in the nerve fibers are associated with the release and re-binding of Ca-ions in the nerve associated with action potential production.
利用雀鳝嗅神经测定了与神经冲动传导相关的机械和热变化。发现动作电位的产生伴随着神经纤维的肿胀。肿胀几乎在动作电位开始时就开始，并在动作电位的峰值时达到顶峰。当冲动沿着纤维传播时，纤维长度会缩短。在室温下，使用响应时间为2 - 3毫秒的热传感器测定了初始热的时间进程。发现正热产生几乎与动作电位同时开始并达到峰值。神经温度升高显示为23（±4）微摄氏度。在10摄氏度至20摄氏度范围内，热产生的温度系数为负，主要是由于低温下正热产生期的延长。负相期间吸收的热量在正相期间释放热量的45%至85%之间变化很大。有人提出，神经纤维中的机械和热变化都与神经中与动作电位产生相关的钙离子的释放和重新结合有关。
