Nitric oxide is involved in lithium-induced immediate early gene expressions in the adrenal medulla

Abstract

This study was conducted to determine if nitric oxide (NO) is involved in lithium-induced expression of c-Fos and inducible cAMP early repressor (ICER) in the adrenal gland. Rats received an intraperitoneal injection of isotonic lithium (76 mg/kg) with either an intracerebroventricle (i.c.v., 250 μg) or intraperitoneal (i.p., 30 mg/kg) Nω-nitro-l-arginine methyl ester (l-NAME) pretreatment. The adrenal expression of c-Fos and ICER was examined by in situ hybridization 1 h after the lithium injection. The cortical c-Fos/ICER expression induced by lithium was not modulated by l-NAME pretreatment. However, lithium-induced medullary expression of c-Fos was attenuated by central l-NAME, and ICER by systemic l-NAME. These results suggest that nitric oxide is, at least partly, involved in lithium-induced c-Fos/ICER expression in the adrenal medulla, and that central nitric oxide may play a different role from peripheral nitric oxide in lithium-induced activation of adrenal medulla.