Aging and ethanol alter neuronal electric membrane properties

The effect of age of donor mouse and acute ethanol exposure on the electrical membrane properties (EMP) of 825 freshly dissociated dorsal root ganglion (DRG) neurons was investigated. Both age and ethanol exerted a number of significant linear and independent effects. Age effects included a 52% increase in action potential overshoot, a 50% increase in a measure of afterhyperpolarization duration, a 31% increase in action potential duration due to decreased rate of repolarization and depolarization, and decreased electrical excitability. Also, specific membrane resistance increased and specific membrane capacitance decreased while the membrane time constant was not significantly affected by age. These EMP alterations with age for freshly dissociated DRG neurons are consistent with those reported previously for cultured DRG neurons and hence further support the hypothesis that the EMP of neurons in situ change significantly with age. Acute ethanol exposure caused relatively few EMP alterations including decreased electrical excitability, specific membrane capacitance, time constant, and overshoot; specific membrane resistance was increased. These changes are similar to those seen previously and are consistent with a membrane expansion effect of ethanol.