Dexamethasone induces different wheel running activity than corticosterone through vasopressin release from the suprachiasmatic nucleus

During the analysis of wheel running activity, we found that corticosterone (1 mg/100 g BW) injection decreased wheel activity, while dexamethasone (0.1 mg/100 g) increased the activity. To clarify the functional differences between corticosterone and dexamethasone, we measured Arg-vasopressin (AVP) release from the suprachiasmatic nucleus (SCN) slice culture in vitro and AVP coding mRNA in the SCN in vivo. The corticosterone (0.2 and 2 mug/ml, final concentration in medium) decreased the AVP release, while it increased by dexamethasone (0.2 and 2 mug/ml). An AVP mRNA in the SCN was decreased by both corticosterone (I mg/100 g) and dexamethasone (0.1 mg/100 g). The differences in wheel activity by corticosterone and dexamethasone are discussed from the changes of AVP in the SCN. (C) 2004 Elsevier B.V. All rights reserved.