Altered amygdalar CRF release and increased anxiety-like behavior in Sardinian alcohol-preferring rats: a microdialysis and behavioral study

Abstract

Background: Dysregulation of the stress-regulatory corticotropin-releasing factor (CRF) system in the central nucleus of the amygdala (CeA) may be a factor in genetically determined alcohol preference.

Methods: To test this hypothesis, basal and restraint stress-induced CRF efflux in the CeA was determined by microdialysis in Sardinian alcohol-preferring (sP) and nonpreferring (sNP) rats. In addition, differences in anxiety-like behavior between sP and sNP rats were evaluated by using the elevated plus maze and conditioned defensive burying tests.

Results: Basal dialysate CRF levels in the CeA were elevated in the alcohol-preferring line (sP, 281.2+/-83.96 pg/ml; sNP, 70.2+/-16.76 pg/ml; p < 0.05). In contrast, no differences in whole-tissue CRF content in the CeA were observed (sP, 1143+/-142 ng/mg protein; sNP, 1181+/-139 ng/mg protein). Restraint stress elevated CRF dialysate concentrations in both sP and sNP rats. Rats of the sP line exhibited more anxiety-like behavior than sNP rats in the elevated plus maze but not in the conditioned defensive burying test.

Conclusions: The results suggest that ethanol-preferring sP rats show a dysregulation in basal CRF release within the CeA that may, in turn, heighten ethanol intake and increase susceptibility to anxiogenic stimuli in these animals.