Cardiac spinal deafferentation significantly delayed the onset of the decompensatory phase of blood loss in conscious rats, whereas cardiac vagal deafferentation slightly potentiated it.
Does cardiac vagal or spinal deafferentation alter the hemodynamic response to blood loss in conscious rats?
In conscious rats, cardiac spinal signals rather than vagal signals are primarily responsible for triggering the decompensatory hemodynamic response to severe blood loss.
The hemodynamic response to progressive blood loss passes through three distinct phases: an initial normotensive compensatory phase, a secondary hypotensive decompensatory phase, and a posthemorrhage recompensatory phase. The role of cardiac vagal and cardiac spinal signals in triggering the different phases of the response to hemorrhage was evaluated in the unanesthetized, freely moving rat by observing the effects on the response to 30% blood loss of prior cardiac vagal deafferentation (bilateral vagal rhizotomy) or prior cardiac spinal deafferentation (bilateral stellate ganglionectomy). In comparison to control animals, it was found that (i) cardiac spinal deafferentation significantly delayed the onset of the decompensatory phase, and (ii) cardiac vagal deafferentation slightly potentiated the decompensatory phase and impaired the recompensatory phase. These results indicate that it is cardiac spinal signals, rather than cardiac vagal signals, which in the conscious rat contribute to the triggering and progression of the decompensatory response to blood loss.
Troy et al. (Fri,) conducted a other in Blood loss. Cardiac vagal deafferentation or cardiac spinal deafferentation vs. Control animals was evaluated on Hemodynamic response to 30% blood loss (onset of decompensatory phase and recompensatory phase). Cardiac spinal deafferentation significantly delayed the onset of the decompensatory phase of blood loss in conscious rats, whereas cardiac vagal deafferentation slightly potentiated it.