The effects of putative amino acid neurotransmitters on somata isolated from neurons of the locust central nervous system.

Changes in spike frequency, membrane potential and input resistance of somata freshly isolated from neurons in the metathoracic ganglia of adult locusts (Schistocerca gregaria) during bath and ionophoretic application of putative amino acid transmitters and analogues were studied using intracellular techniques. gamma-Aminobutyrate, glycine, taurine, cysteine and DL-ibotenate hyperpolarized the isolated soma, the response to kainic acid was depolarizing whereas L-glutamate and L-aspartate evoked a variety of potential changes. All of these compounds reduced the input resistance of the isolated soma. Ionophoretic studies showed that the receptors for L-glutamate and gamma-aminobutyrate are diffusely distributed over the somal surface.