抄録
Somatic afferent regulation of heart rate by noxious knee joint stimulation has been proven, in anesthetized cats, to be a reflex response whose reflex center is in the brain and efferent arc is a cardiac sympathetic nerve. In the present study, we examined whether articular stimulation could influence heart rate by this efferent sympathetic pathway in spinalized rats. In central nervous system (CNS)–intact rats, noxious articular movement of either the knee or elbow joint resulted in an increase in cardiac sympathetic nerve activity and heart rate. However, while in acutely spinalized rats, noxious movement of the elbow joint resulted in a significant increase in cardiac sympathetic nerve activity and heart rate, noxious movement of the knee joint had no such effect and resulted in only a marginal increase in heart rate. The fact that this marginal increase in heart rate was abolished by adrenalectomy suggests that it was due to the release of adrenal catecholamines. In conclusion, the spinal cord appears to be capable of mediating, by way of cardiac sympathetic nerves, the propriospinally-induced reflex increase in heart rate that follows noxious stimulation of the elbow, but not knee, joint.
