CHANGES IN PAROXETINE BINDING IN THE CEREBRAL-CORTEX OF POLYDIPSIC RATS

Schedule-induced polydipsia was induced when food-deprived rats were s ubjected to a fixed-time (60 s) feeding schedule for 150 min daily for 3 weeks (training period). Subsequent chronic administration of the s erotonin reuptake inhibitor fluoxetine reduces schedule-induced polydi psia over 2-4 weeks. We asked whether changes in the serotonin reuptak e carrier occur following the development of schedule-induced polydips ia and its reduction by fluoxetine. Using [H-3]paroxetine binding, we found a 40% increase in K-d and a 50% decrease in B-max in polydipsic rats; both were reversed by fluoxetine. Food deprivation alone did not affect these parameters. These observations suggest that changes in t he serotonin reuptake carrier correlate with the development and rever sal of schedule-induced polydipsia.