Cardiopulmonary sympathetic and vagal afferents excite C1–C2 propriospinal cells in rats

Abstract

The purpose of this study in anesthetized rats was to determine the effects of stimulating cardiopulmonary sympathetic afferents (CPSA) and vagal afferents on C1–C2 descending propriospinal neurons. We hypothesized that inhibition of spinal sensory neurons produced by CPSA or vagus activation might relay in C1–C2 spinal segments. Extracellular action potentials were recorded from 73 C1–C2 neurons whose axons were antidromically activated in lumbar segments. CPSA input excited 22 cells, inhibited two cells and excited/inhibited one cell, whereas vagal input excited eight cells and inhibited two cells. Results are consistent with the hypothesis that CPSA input can be processed in C1–C2 segments to produce neural modulation in distant spinal segments.