Hiromi Osanai

Corticosterone rapidly modulates AMPA receptor-driven Ca2+ signals in mouse hippocampal CA1 region

cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), protein kinase G inhibitor KT5823, cGMP analogue 8-bromo-cGMP (8-Br-cGMP), peroxynitrite donor 3-morpholinosydnonimine (SIN-1) or RyR blocker dantrolene for a period of 9–13 DIV. Treatment with L-NAME led to a significant decrease in NO2 level in the culture medium and intracellular cGMP level during the culture for 24 h. L-NAME, ODQ, and KT5823 markedly decreased 5′-bromo-2′-deoxyuridine (BrdU) incorporation into the NPCs the proliferative activity. Contrariwise, SIN-1 significantly increased BrdU incorporation. 8-Br-cGMP partially abolished the decrease in BrdU incorporation by L-NAME. However, no significant change was observed in lactate dehydrogenase released into the culture medium during treatment with any drugs. Treatment with dantrolene was effective in decreasing BrdU incorporation and NO2 level in the culture medium. RT-PCR analysis revealed that there mainly exist RyR3 of RyR1, RyR2, and RyR3 in the NPCs. These results suggest that RyR-mediated Ca2+ release from endoplasmic reticulum is essential for proliferative activity through activation of NO/cGMP pathway in the hippocampal NPCs of embryonic mice.