Morphological alterations of retinal cells accompanying inhibition of axonal transport by kainic acid.

The effect of kainic acid (KA) on rat retinal morphology was investigated with emphasis on the ganglion cell layer. Two hours after intraocular injection of KA, 70% of the neurones in the ganglion cell layer display morphological alterations. These alterations at the ultrastructural level include the absence of identifiable Golgi complexes and the presence of abundant round empty vacuoles among other nuclear and cytoplasmic modifications. These alterations of the Golgi complex are discussed in relation to axoplasmic transport inhibition by kainic acid. Seven days after KA treatment the retina showed a decreased number of cells in the inner nuclear layer and ganglion cell layer and the inner plexiform layer had virtually disappeared. Despite the disappearance of cells from the ganglion cell layer a week after KA injection, abundant ganglion cells could be retrogradely labelled with horseradish peroxidase. Thus although retinal ganglion cells seem to be sensitive to KA most of them survive KA treatment.