NEUROTRANSMITTERS OF MOTOR-NEURONS IN THE STOMATOGASTRIC GANGLION OF AN ISOPOD CRUSTACEAN, LIGIA-EXOTICA

Neurotransmitters of motor neurons in the foregut muscles of an isopod Ligia exotica were identified by recording changes in membrane potent ial to exogenously applied glutamate and acetylcholine. The effects of antagonists, tubocurare and joro spider toxin, on excitatory junction al potentials evoked by nerve stimulation and by iontophoretic applica tion of glutamate and acetylcholine provided additional evidence for i dentification, The junctional receptors were desensitized by putative neurotransmitters. Glutamate is a candidate as an excitatory neurotran smitter at the neuromuscular junctions in intrinsic muscles of the gas tric mill and pylorus, and acetylcholine is a candidate in the extrins ic muscles of the gastric mill and cardiopyloric valve. (C) 1998 Elsev ier Science Inc. All rights reserved.