Effect of SA4503, a novel σ1 receptor agonist, against glutamate neurotoxicity in cultured rat retinal neurons

We examined the effects of sigma(1) receptor agonists against glutamate-induced neurotoxicity in cultured retinal neurons. Primary cultures obtained from fetal rat retinas (16-19 d gestation) were used. The neurotoxic effect of glutamate was quantitatively assessed using the trypan blue exclusion method. A brief exposure of retinal cultures to glutamate (500 mu M) led to delayed neuronal cell death. The glutamate-induced neurotoxicity was inhibited by (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo-[a,b]-cyclohepten-5,10-imine hydrogen maleate (MK-801). The sigma(1) receptor agonists, 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)-piperazine dihydrochloride (SA4503) and(+)-pentazocine at a concentration range of 0.1 similar to 100 mu M reduced the glutamate-induced neurotoxicity in a dose-dependent manner. In addition, the neuroprotective effects of both SA4503 and (+)-pentazocine were antagonized by co-treatment with N, N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine monohydrochloride (NE-100), a putative sigma(1) receptor antagonist. These findings suggest that sigma(1) receptor agonists protect retinal cells against glutamate-induced neurotoxicity. (C) 1998 Elsevier Science B.V.