Response to light of various retinal cell types during spreading depression.

The retina in low Cl-media gives rise to spreading depression (SD) accompanied by a large, receptor side negative potential change (SDP). Changes during SD in the membrane potential and the responsiveness to light of various retinal cell types are studied, using a pair of intra- and extracellular electrodes and applying dim white light flashes to the retina at 5 sec intervals throughout the experiment. The study shows that the amacrine and ganglion cells depolarize strongly during SD to complete loss of response to light, and that the start of depolarization in these cell types precedes a little that of SDP. The other cell types continue to respond to light flashes during SD, though their response amplitude decreases as the cells depolarize due probably to an increase in [K+]0 accompanying SD. The results suggest that the amacrine and ganglion cells take an initiative role in the SD generation, and that the changes in the other cell types are mostly of passive nature.