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 potential to exogenously applied glutamate and acetylcholine. The effects of antagonists, tubocurare and joro spider toxin, on excitatory junctional potentials evoked by nerve stimulation and by iontophoretic application of glutamate and acetylcholine provided additional evidence for identification. The junctional receptors were desensitized by putative neurotransmitters. Glutamate is a candidate as an excitatory neurotransmitter at the neuromuscular junctions in intrinsic muscles of the gastric mill and pylorus, and acetylcholine is a candidate in the extrinsic muscles of the gastric mill and cardiopyloric valve.