ANTAGONISM OF CENTRAL CRF SYSTEMS MEDIATES STRESS-INDUCED CHANGES IN NORADRENALINE AND SEROTONIN TURNOVER IN RAT-BRAIN REGIONS

The present study was conducted to test the hypothesis that central co rticotropin-releasing factor (CRF) systems mediate the changes in the dynamics of brain noradrenergic and serotonergic systems induced by el ectric footshock stress. Serum corticosterone concentrations were dete rmined fluorometrically and brain monoamine contents (noradrenaline, s erotonin and their metabolites) in five brain regions in rats were mea sured by high-performance liquid chromatography with electrochemical d etection 10 and 40 min after exposure to electric footshock stress for 1 hour: Intracerebroventricular administration of a CRF antagonist, a lpha-helical CRF9.41 (100 mu g), had no effect on serum corticosterone concentrations in either normal or stressed animals. However, electri c footshock stress-induced increases in noradrenaline turnover were si gnificantly reduced by the administration of alpha-helical CRF9.41, in the amygdala and septum at both time points after exposure to electri c footshock stress. In contrast, electric footshock stress-induced inc reases in serotonin turnover in all of the brain regions were further elevated by the administration of alpha-helical CRF9.41, in almost all of the brain regions examined. These results suggest that central CRF neuronal systems are involved in mediating the electric footshock str ess-induced changes in the dynamics of brain noradrenergic and seroton ergic systems in rats. (C) 1998 Prous Science. All rights reserved.