Effect of somatostatinergic analogues on the ischemia-induced release of [3H]-D-aspartate and [3H]-GABA from rat retina and hippocampus

Abstract

The modulation of the enhanced release of [3H]-D-Aspartate and [3H]GABA following ischemia-like conditions was studied in rat retinal and hippocampal preparations using a superfusion system. Ischemia was simulated by a glucose-free medium equilibrated with 95%N2/5%CO 2. In this model the potential neuroprotective effect somatostatin on [3H]-D-Aspartate and [3H]GABA release induced by ischemia-like conditions were investigated. Retina was more resistant to ischemia compared to hippocampus. Somatostatin (SRIF-14) decreased ischemia-induced [3H]GABA release in both retina and hippocampus while the the sst2/5 somatostatin receptor selective agonist Octreotide decreased and the sst2 somatostatin receptor selective antagonist D-Tyr8 CYN 154806 increased the ischemia-induced [ 3H]-D-Aspartate from both retinal and hippocampal preparations indicating that endogenous somatostatin plays a neuroprotective role in both tissues through sst2 receptor activation, at least as far as the ischemia-induced [3H]-D-Aspartate release is concerned. ©PHARMAKON-Press.