麻酔ラットにおける体性ー卵巣交感神経反射電位の解析

抄録

The spinal and supraspinal components of both A- and C- reflexes were studied in the somato-ovarian sympathetic reflex discharges elicited by a single shock either to a spinal (T9-11) afferent nerve or to a limb (tibial) afferent nerve in urethane anesthetized rats. In central nervous system (CNS) intact rats, a single shock to a T9-11 spinal afferent nerve produced early and late A-reflex discharges with latencies of about 51 ms and 117 ms, respectively, and a C-reflex with a latency of about 200 ms in a ovarian sympathetic efferent nerve. After spinalization at the third thoracic level, stimulation of the same spinal afferent nerve produced an A-reflex with the same latency as the early A-reflex in CNS-intact rats and a C-reflex discharge with a latency of about 112 ms. On the other hand, a single shock to a tibial afferent nerve evoked an A-reflex discharge with latency of about 91 ms, and a C-reflex discharge with a latency of about 228 ms in CNS-intact rats. In most cases, the A-reflex could be divided into two subcomponents of different latencies. These A- and C- reflex discharges elicited by stimulation of a tibial afferent nerve were not observed after spinalization. It was concluded that ovarian sympathetic A- and C- reflex discharges evoked by stimulation of a segmental spinal afferent nerve in CNS-intact rats are of spinal and supraspinal origin, and those evoked by tibial nerve stimulation are of supraspinal origin. [J Physiol Sci. 2006;56 Suppl:S95]