Dynamic changes in phrenic motor output following high cervical hemisection in the decerebrate rat.

Dynamic changes in phrenic motor output following high cervical hemisection in the decerebrate rat.
Exp Neurol. 2015 Jun 6;
Authors: Ghali MG
Abstract
Hemisection of the spinal cord at C2 eliminates ipsilateral descending drive to the phrenic nucleus and causes hemidiaphragmatic paralysis in rats. Phrenic nerve (PhN) or diaphragmatic activity ipsilateral to hemisection can occasionally be induced acutely following hemisection by respiratory stressors (i.e., hypercapnia, asphyxia, contralateral phrenicotomy) and becomes spontaneously active days-to-weeks later. These investigations, however, are potentially confounded by the use of anesthesia, which may suppress spontaneously-active crossed phrenic pathways. Experiments were performed on vecuronium-paralyzed, unanesthetized, decerebrate adult male rats and whole PhN activity recorded continuously before, during, and after high cervical hemisection at the C1 spinal level. Crossed phrenic activity recovered spontaneously over minutes-to-hours with maximal recovery of 11.8±3.1% (m±SE). Additionally, there was a significant increase in contralateral PhN activity of 221.0±40.4% (m±SE), as measured by changes in PhN activity contralateral to HSx; since animals were artificially-ventilated, these changes likely represent an increase in central respiratory drive. These results underscore the state-dependence of crossed bulbophrenic projections and suggest that unanesthetized models may be...

Source: Experimental Neurology - June 6, 2015 Category: Neurology Authors: Ghali MG Tags: Exp Neurol Source Type: research