Excitatory and inhibitory amino acids and peptide-induced responses in acutely isolated rat spinal dorsal horn neurons.

The responses to excitatory and inhibitory amino acids and peptides were investigated in isolated rat spinal dorsal horn neurons (laminae I-V) of young rats using the whole-cell voltage-clamp technique. The treatment of spinal slices with low concentrations of enzymes and mechanical dissociation yielded isolated neurons that were sensitive to excitatory amino acids (glutamate, kainate, quisqualate and N-methyl-D-aspartate (NMDA), inhibitory amino acids (gamma-aminobutyric acid (GABA), glycine) and peptides (substance P, calcitonin gene-related peptide (CGRP). The responses of dorsal horn neurons to NMDA were potentiated by glycine and CGRP, whereas GABAA responses were enhanced by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA). Our observations indicate that there is reasonable agreement between many of the responses of isolated neurons and those studied in in vivo and in vitro slice and culture preparations.