Glutamate receptors expressed in Xenopus oocyte by messenger RNA from invertebrate muscle.

Glutamate induced responses in the surface membrane of Xenopus oocyte by injection with mRNA from crustacea and insect muscle. Glutamate (10(-5) to 10(-4) M) elicited smooth current responses which resembled those induced by kainate. This smooth current reversed direction at about 0 mV and was blocked by a spider toxin (JSTX). Higher concentrations (more than 1 x 10(-3) M) of glutamate induced JSTX-insensitive oscillatory current responses which may be caused by Cl- activation.