[Abstract Title]. - Society for Neuroscience

P rats provided by the Indiana Alcohol Res Ctr, supported by NIH grant R24
AA015512
NIH Grants AA10567 and AA13881
Title: Daily administration of melatonin reduces ethanol drinking in female ethanol-preferring
(P) rats
Authors: D. D. RASMUSSEN 1 , *T. H. WOLDEN-HANSON 2 , K. M. MCKELVEY 1 ;
1 116-MIRECC, VA Puget Sound Hlth. Care Syst and Dept Psychiatry, Univ. Washington,
Seattle, WA; 2 S-182-GRECC, VA Puget Sound Hlth. Care Syst., Seattle, WA
Abstract: Chronic ethanol and withdrawal disrupts secretion of the hormone melatonin.
Melatonin has been demonstrated to regulate circadian rhythm physiology, autonomic function,
anxiety, forebrain endogenous opioid activity, and stress responses - i.e., functions which all are
altered during and after chronic ethanol abuse and which all have been suggested to have roles in
modulating ethanol intake and relapse. Accordingly, we tested the hypothesis that melatonin
treatment will suppress ethanol drinking in rats selectively-bred for increased ethanol preference
and intake (P line). Adult male and female P rats were provided food and three-bottle choice
between 0, 15 and 30% (v/v) ethanol 24 hours/day, 7 days/week. After 7 weeks, Melatonin (1
κg/ml) or vehicle Control (0.01% ethanol) was added to all three fluids, which were consumed
primarily (84%) at night. Two weeks after initiation of Melatonin vs Control treatment, the 15
and 30% ethanol solutions were removed for 2 weeks and then reinstated for 2 weeks, repeated
for a total of 4 consecutive ethanol deprivation/reinstatement cycles. Pre-treatment baseline total
(15% + 30%) ethanol intake was 6.2+/-0.3 and 5.2+/-0.3 g/kg BW/24 hours for the females and
males, respectively. For females, ethanol intake decreased (p