Intraocular injections of kainic acid produce marked lesions of the chicken retina. Low doses (6-20 nmol/retina) appear to cause lesions of the inner part of the retina, primarily involving amacrine cells. At around 60 nmol/retina there is a qualitative change in the nature of the lesion, as the horizontal and bipolar cells begin to degenerate. Higher doses of kainic acid lead to disappearance of both the outer and inner plexiform layers. At all doses used, the photoreceptors and ganglion cells survive exposure to kainic acid. Low doses of kainic acid reduce the content of the amacrine and horizontal cell markers acetylcholine and gamma-amino-butyric acid, but have little effect upon taurine. These results are consistent with a role for glutamic and/or aspartic acid as bipolar cell and photoreceptor transmitters.