GABA DECREASES IN THE SPINAL-CORD DORSAL HORN AFTER PERIPHERAL NEURECTOMY

A significant fall in the number of GABA-immunoreactive cells in lamin ae I-III of the rat spinal cord occurred in the somatotopic area of pr ojection of the sciatic nerve after nerve transection. The decrease st arted at 2 weeks post-neurectomy, and at 4 weeks ipsilateral mean cell numbers were approximately 72% of contralateral control values. Simil arly, the concentration of GABA in spinal homogenates was significantl y reduced 4 weeks post-neurectomy. These data, together with our recen t finding of an increase in spinal GABA during chronic inflammation of the hindlimb, suggest that the level of GABA in the dorsal horn is re gulated by the amount of primary afferent input.