The study clarifies the representation of the exercise pressor reflex within the central nervous system, establishing its characteristics at several levels of neuraxis integration in a feline model.
Should not change clinical practice; extends mapping of neuraxial sites for the exercise pressor reflex in animals.
The pressor reflex evoked by muscular contraction (exercise pressor reflex) is one important model of cardiovascular adjustments during static exercise. The central nervous system (CNS) structures mediating this reflex have remained largely obscure. Therefore, we examined the contribution of selected levels of the neuraxis in mediating the pressor reflex evoked by muscular contraction from stimulation of ventral roots. Decerebrate cats exhibited larger pressor reflexes than those found in intact alpha-chloralose-anesthetized cats, a difference more apparent at low (5 Hz or repeated twitch) rather than at high (50 Hz or tetanic) stimulus frequencies. Although a depressor response to 5-Hz stimulation was observed in the intact anesthetized cats, it appeared to be primarily due to anesthetic level, since a depressor response was not observed in decerebrate animals (nonanesthetized). Cerebellectomy produced no changes in the reflexes of the decerebrate animal. Further transection of the neuraxis (caudal to the midcollicular level) attenuated the exercise pressor reflex. The spinal cat demonstrated slight evidence of exercise pressor reflex activity. These results provide clarification as to representation of this pressor reflex within the CNS and establish the reflex's characteristics at several levels of neuraxis integration.
No takes yet. Share an insight, caveat, or question.
Iwamoto et al. (1985) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: