The effect of age on energy metabolism and resistance to ischaemic conduction failure in rat peripheral nerve.

Caudal nerve conduction velocity and amplitude of nerve action potential increased progressively with age to 8 months after which time no further increases were demonstrated. Rat peripheral nerve was progressively more resistant to ischaemic-anoxic conduction failure with increasing age. This resistance to ischaemic conduction failure was paralleled by a progressive age-related decline in endoneurial O2 consumption. Endoneurial adenosine triphosphate and creatine phosphate values were also progressively reduced with age. 15 min of anoxia resulted in progressively smaller reductions in these nucleotide phosphates with increasing age to 8 months after which time little further change occurred. Nerve lactate response to anoxia was higher in young rats (1 and 2 months) than in older animals (8 and 21 months). High energy phosphate expenditure progressively declined with age to 8 months, then stabilized. These findings indicate that the major mechanism of resistance to ischaemic conduction failure is a progressive decline in energy requirements.