S-Space College of Medicine/School of Medicine (의과대학/대학원) Dept. of Medicine (의학과) The Seoul Journal of Medicine The Seoul Journal of Medicine Vol. 30 No.4 (1989)
Physiological Properties of the Spinal Dorsal Horn Cells Receiving Ventral Root Afferent Inputs in the Cat
고양이에서 척수전근 구심섬유의 흥분을 받는 척수후각 신경세포의 생리학적 특성
- Issue Date
- Seoul J Med, Vol.30 No.4, pp. 203-211
- Ventral root afferent ; High threshold cell ; Wide dynamic range cell ; Peripheral nerve inputs ; Morphine
- Spinal dorsal horn neurons receiving ventral root afferent inputs were studied
in cats anesthetized with a -chloralose. The L7 and S1 spinal ventral roots were stimulated
electrically, and after identifying the evoked single cell activities, their receptive fields, cell
types and peripheral nerve inputs were determined. Followings are the results obtained.
1. A total of 43 cells receiving ventral root afferent inputs were identified. These were
located in lamina IV-VI of the spinal cord. More than half of them were silent or showed
spontaneous discharge less than 5 Hz during the resting period. The remaining units discharged
spontaneously in the range of 10-20 Hz.
2. In 23 cells, the cell types were determined according to the responses to graded
mechanical stimulation applied to receptive fields. Eleven cells were HT cells and seven were
3. All these cells were activated by C-intensity stimulation but not by A0 -stimulation of the
ventral roots, while their main peripheral nerve inputs were A0 -inputs.
4. Intravenous morphine inhibited the reponses of these cells to VR stimulation, and
naloxone reversed the morphine effect.
From the above results it was concluded that afferent inputs carried by the VRA fibers
might be associated with still unknown pain pathways.