PT  - JOURNAL ARTICLE
AU  - Andre L. Curtis
AU  - Luis A. Pavcovich
AU  - Rita J. Valentino
TI  - Long-Term Regulation of Locus Ceruleus Sensitivity to Corticotropin-Releasing Factor by Swim Stress
DP  - 1999 Jun 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 1211--1219
VI  - 289
IP  - 3
4099  - http://jpet.aspetjournals.org/content/289/3/1211.short
4100  - http://jpet.aspetjournals.org/content/289/3/1211.full
SO  - J Pharmacol Exp Ther1999 Jun 01; 289
AB  - Corticotropin-releasing factor (CRF) acts as a putative neurotransmitter in the locus ceruleus (LC) to mediate its activation by certain stressors. In this study, we quantified LC sensitivity to CRF 24 h after swim stress, at a time when behavioral depression that is sensitive to antidepressants is apparent. Rats were placed in a tank with 30 cm (swim stress) or 4 cm water and 24 h later, either behavior was monitored in a forced swim test or LC discharge was recorded. Swim stress rats were more immobile than control animals in the swim test. LC neurons of swim stress rats were sensitized to low doses of CRF (0.1–0.3 μg i.c.v.) that were ineffective in control animals and were desensitized to higher doses. Swim stress selectively altered LC sensitivity to CRF because neither LC spontaneous discharge nor responses to other agents (e.g., carbachol, vasoactive intestinal peptide) were altered. Finally, the mechanism for sensitization was localized to the LC because neuronal activation by low doses of CRF was prevented by the intracerulear administration of a CRF antagonist. CRF dose-response curves were consistent with a two-site model with similar dissociation constants under control conditions but divergent dissociation constants after swim stress. The results suggest that swim stress (and perhaps other stressors) functionally alters CRF receptors that have an impact on LC activity. Stress-induced regulation of LC sensitivity to CRF may underlie behavioral aspects of stress-related psychiatric disorders. The American Society for Pharmacology and Experimental Therapeutics