Action potential duration increases as body temperature decreases during hibernation

Area of Science:

• Neuroscience
• Physiology
• Mammalian Biology

Background:

• Temperature influences neuronal firing patterns, affecting action potential duration.
• Previous studies explored temperature effects on neurons in vitro and in anesthetized mammals.
• Hibernation involves significant body temperature reduction, impacting physiological processes.

Purpose of the Study:

• To investigate the effect of reduced body temperature on neuronal action potential duration in behaving animals.
• To determine if temperature-induced changes in neuronal biophysics during hibernation are reversible.

Main Methods:

• Recorded oscilloscope traces of neuronal action potentials from brainstem and thalamic neurons in ground squirrels.
• Measured action potential duration at normal body temperature (euthermia) and during hibernation (low body temperature).
• Compared action potential durations between euthermic and hibernating states, and after arousal.

Main Results:

• Action potential duration significantly increased at lower body temperatures during hibernation (P < 0.01).
• The observed increase in action potential duration was reversible upon arousal from hibernation.
• This study provides the first evidence in behaving animals of biophysical changes in central nervous system neurons at low body temperatures.

Conclusions:

• Reduced body temperature during hibernation alters the biophysical characteristics of central nervous system neurons.
• These alterations in neuronal membrane properties likely modify neuronal function and information processing during hibernation.
• The findings highlight the adaptability of neuronal function to extreme physiological conditions like hibernation.