Corticosterone activates Erk1/2 mitogen-activated protein kinase in primary hippocampal cells through rapid nongenomic mechanism

Nongenomic effects of glucocorticoids (GC) in various cell types have been well documented, but it still remains unknown whether the mechanism also works in hippocampus which is a crucial target of glucocorticoids in neural system during physiological and/or pathophysiological processes. We present here that corticosterone (B) could rapidly activate Erk1/2 mitogen activated protein kinase (MAPK) in primarily cultured hippocampal cells within minutes, with a bell shaped time dependent curve which peaked at 15min and then went down to normal level in 30 min. This activation was blocked by protein kinase C (PKC) inhibitor (G6976), G protein inhibitor (GDPs), and MEK(MAPK/extracellular signal regulated kinase kinase) inhibitor(PD98059), but not by protein kinase A (PKA) inbibitor (H89), tyrosine kinase inhibitor (genistein), and glucocorticoid receptor (GR) antagonist (RU38486). Thus, the rapid activation of Erk1/2 MAPK in primary hippocampal cells induced by B was likely mediated by a G protein coupled receptor (GPCR) pathway with involvement of PKC, which belonged to the nongenomic rather than genomic mechanism of GC’s effects.