Serotonergic responses to corticosterone and testosterone in the limbic system

Glucocorticoids secreted peripherally during stressful events act on centra l monoaminergic systems. In particular, serotonergic mediation of social be havior, such as aggression and reproduction, may be affected by glucocortic oids. This study was undertaken to determine if systemically administered c orticosterone would rapidly affect central monoaminergic activity. Male Ano lis carolinensis (N = 8 each group) were injected intraperitoneally with 10 or 100 mu g corticosterone, 10 mu g testosterone, or saline. Twenty minute s after treatment, brains were rapidly dissected and frozen and then microd issected (punch diameter 300 mu m) and analyzed by highperformance liquid c hromatography. Serotonergic turnover (estimated by S-hydroxyindoleacetic ac id/serotonin) in the hippocampus and medial amygdala was significantly enha nced by systemic corticosterone. Both of these regions of the brain have be en associated with social stress. Testosterone also enhanced turnover in th e hippocampus. The effect of corticosterone and testosterone may be to modu late socially induced differences in serotonergic response. Rapid, but shor t-lived, glucocorticoid stimulation of serotonin release suggests a possibl e mechanism for mediation of changing social behavioral events. (C) 2000 Ac ademic Press.