Peculiarities of receptor-channel complexes for inhibitory mediators in the membranes of lamprey spinal cord neurones.

Effects of inhibitory mediators on the membranes of isolated lamprey spinal cord neurones were investigated by means of whole-cell recording and concentration clamp techniques. Glycine and gamma-aminobutyric acid (GABA) applications evoked desensitizing chloride currents. The concentrations at half-maximum effects were 16 microM for glycine- and 1.5 mM for GABA-activated currents. Ionic responses to applications of both amino acids demonstrated full cross-desensitization. Strychnine and bicuculline suppressed both glycine- and GABA-activated conductances to the same degree. We suggest that in the membranes of lamprey spinal cord neurones glycine and GABA act on the same receptor-channel complexes.