CHRONIC SOCIAL STRESS INCREASES LEVELS OF PREPROGALANIN MESSENGER-RNAIN THE RAT LOCUS-COERULEUS

Galanin is a 29 amino acid neuropeptide that coexists with norepinephr ine in approximately 80% of locus coeruleus (LC) neurons in the rat. T he effects of chronic, naturalistic stress on preprogalanin mRNA in th e LC was studied. The visible burrow system (VBS) served as the stress paradigm. Long-Evans rats (three males and two females) were housed t ogether in the VBS for 13 days. The males established dominance hierar chies during this period. On day 14, preprogalanin mRNA in the LC was significantly elevated in subordinate rats compared to dominant and co ntrol rats, as measured by quantitative in situ hybridization. Levels of mRNA were positively correlated with the number of wounds by day 7 and day 14 and negatively correlated with body weight gain by day 14. These results suggest that the neuropeptide galanin may be overexpress ed during chronic stress in rats.