Electrophysical responses of isolated locust (Schistocerca gregaria) somata to taurine and GABA application

The comparative effects of applied taurine and GABA on isolated locust neural somata has been studied. Iontophoretically applied taurine and GABA both hyperpolarized and decreased membrane resistance in the preparation. GABA was markedly the more potent of the two amino acids in this respect. Both amino acids showed similar reversal potentials (around -75 mV) when tested on somata held at a series of membrane potentials. The actions of both amino acids were antagonized by picrotoxin and the proposed specific taurine antagonist 6-aminomethyl-3-methyl-4H-1,2,4-benzthiadiazine-1,1 dioxide hydrochloride. Responses to both amino acids were augmented by the benzodiazepine flunitrazepam. The data suggest that taurine and GABA act at a common site in locust somata.