Nancy E. Badia-Elder, Ph.D.
COMPANY: Indiana University-Purdue University
Advisor: Dr. Stephen Kiefer
Alcohol related traits in rats selectively bred for sensitivity to serotonin agonists.
Ten serotonin deficient Fawn-Hooded (FH) and 11 Wistar stock rats along with 10 HI and 10 LO (rats selectively bred for both high and low hypothermic responses to the serotonin agonist, 8-OH-DPAT) were tested for alcohol related traits. First, all rats were tested for taste reactivity responding to a range of alcohol concentrations, water, sucrose, and quinine both prior to and following experience with 3 weeks of two-bottle (10% alcohol, water) consumption testing. Second, rats were tested for fluid balance during 24 hr of fluid deprivation. Third, rats were tested for alcohol consumption following injections of the serotonin agonist, fenfluramine. As a final measure, the effects of fenfluramine on c-fos immunoreactivity was examined in five brain areas. Neither FH and Wistar nor HI and LO rats differed in alcohol consumption, however, FH rats consumed significantly more total fluid (alcohol and water) relative to Wistar rats. In comparison to Wistar rats, FH rats made more ingestive and less aversive taste reactivity responses to all alcohol concentrations, water, and quinine; reactivity to sucrose was high for both groups. When tested for fluid balance during fluid deprivation, all rats produced similar amounts of urine output. Following injections of fenfluramine, FH, as well as HI and LO rats, decreased alcohol consumption. All rats showed increased C-fos immunoreactivity in response to fenfluramine in only one brain area examined, the central nucleus of the amygdala (CeA). The effect of fenfluramine on c-fos immunoreactivity in the CeA indicates that this brain area is sensitive to the central actions of the serotonin agonist. It appears that FH rats are polydipsic animals as reflected by their high fluid intake and high ingestive responding during taste reactivity testing. The results from the present study suggest that decreased serotonergic activity may affect consummatory behaviors in general rather than alcohol responses specifically.
Ph.D., Psychology, Kansas State University, 1995