Abstract

Ischemic neuropathy has a well-recognized but unexplained tendency to spare unmyelinated (C) fibers such as those that subserve pain. We investigated whether low energy requirement plays a part in this selectivity, by comparing the abilities of Aβ, Aδ, and C fibers in cervical vagus nerve of rabbit at 38°C to maintain excitability in the presence of severe hypoxia. We found that, given enough glucose, many C fibers and some Aδ fibers, but not Aβ fibers, can withstand complete anoxia for an apparently unlimited period.