Kainic acid differently affects retinal projections to different pretectal nuclei

Kainic acid (KA) damages retinal cells, thus impairing axonal anterograde transport of labeled aminoacids when injected intravitreally. In this study, Long-Evans rats were injected with KA into one eye, and seven days later were binocularly injected with 14C-valine. The extent of residual retinal afferents to two pretectal nuclei was calculated as the percentage of the contralateral, intact side. Projections to the nucleus of the optic tract (first relay station of the optokinetic pathway) appear significantly more affected than those to the olivary pretectal nucleus (involved in the pupillary light response). These results suggest a correlation between the functional properties of retinal ganglion cells and distinctive biochemical characteristics, such as their susceptibility to KA.