THE FUNCTIONAL LINKAGE AMONG THE ZSL-SPINAL DORSAL HORN-SN

Electrical stimulation of the Zusanli point (ZSL) and solitary tract n ucleus (SN) as well as microelectrode recording from the laminae III-V of the lumbar spinal dorsal horn have been used on the pentobarbital anesthetized rats, finding and identifying 57 spinal neurons respondin g to the stimulations of both ZSL and SN. Among them, 34 responded ant idromically to SN; the others responded orthodromically to SN. Among t hem. the low-threshold mechano-receptive (LTM) neurons and wide-dynami c-range (WDR) neurons were 50 percent respectively. The results indica te that (i) a single spinal dorsal horn neuron receives somatic affere nt input a.d then conveys it to the visceral sensory nucleus-SN; (ii) some spinal dorsal horn neurons receive, in turn, innervation from the SN; (iii) the convergence and integration between somatic and viscera l sensory inputs might occur in the spinal dorsal horn neurons and/or SN.