Both amacrine and bipolar cells release glutamate in the rat retina after ischemia/reperfusion insult in vitro

Purpose: To investigate which cells in the inner nuclear layer release glutamate after exposure through the use of a model mimicking rat retina ischemia/reperfusion induced by glucose/oxygen deprivation in vitro. Methods: An in vitro retinal ischemia model was used to monitor the release of glutamate by staining with diaminobenzidine hydrochloride. Immunocytochemistry was used to identify the cells releasing glutamate during ischemic/reperfusion injury. Results: On immunocytochemistry, double-labeling of some amacrine and bipolar cells was observed, with somata being stained blue by GABA and two portions of the processes labeled brown due to glutamate reactivity. Some somata of amacrine cells were double-labeled with calbindin, while horizontal cells were single-labeled with calbindin. Conclusions: During ischemia/reperfusion injury in vitro, both amacrine and bipolar cells release glutamate. These results may be related to the patterns of apoptotic cell death seen in the inner retina.