L-Glutamate depolarizes ON-OFF transient type of amacrine cells in the carp retina: an ionophoretic study.

Amacrine cells generating the ON-OFF transient type of photoresponse, which is most frequently encountered, were identified by intracellular recording and staining with a fluorescent dye Lucifer Yellow in the carp (Cyprinus carpio) retina. L-Glutamate applied ionophoretically slowly depolarized the amacrine cells by about 10 mV and reduced their photoresponses during the application. Such changes gradually recovered following the cessation of L-glutamate injection. The results indicate that this amino acid directly activates the ON-OFF type amacrine cells.