Stimulation of 5-HT1A receptor with 8-OH-DPAT inhibits hydrogen peroxide-induced neurotoxicity in cultured rat cortical cells

We investigated the effect of 8-hydroxy-2-(N,N-dipropylamino)tetralin (8-OH-DPAT), a specific 5-HT1A receptor agonist, on H2O2-induced neuronal cell death in cultured rat cortical cells. H2O2 produced a concentration-dependent reduction of cell viability, which was significantly reduced by (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-imine (MK-801), an N-methyl-d-aspartate (NMDA) receptor antagonist. Pretreatment of 8-OH-DPAT over the concentration range of 1-100 μM significantly inhibited the H2O2 (100 μM)-induced neuronal cell death as assessed by a MTT assay and the number of apoptotic nuclei, evidenced by Hoechst 33342 staining. The protective effect of 8-OH-DPAT (100 μM) was completely blocked by the simultaneous treatment of 1-(2-methoxyphenyl)-4-[4-(2-phthalimideo)butyl]piperazine (NAN-190, 10 μM), a selective 5-HT1A receptor antagonist, but not in the presence of the dopamine receptor blocker spiperone (10 μM), indicating that the protective effect of 8-OH-DPAT was mediated via 5-HT1A receptors. In addition, 8-OH-DPAT inhibited the H2O2-induced elevation of glutamate release into the medium and cytosolic Ca2+ concentration ([Ca2+]c), generation of reactive oxygen species (ROS), and caspase-3 activity. These results suggest that the activation of 5-HT1A receptor with 8-OH-DPAT may ameliorate an oxydative stress-induced apoptosis of neuronal cell by interfering with the increase of [Ca2+]c, and then by inhibiting glutamate release, generation of ROS and caspase activity.