Intracerebroventricular (icv) administration of mouse leptin in rats: Behavioral specificity and effects on meal patterns

Leptin is a protein that is produced primarily in fat tissue and is thought to be a lipostatic feedback signal for the regulation of body fat stores. The purpose of this study was to determine the behavioral specificity of i. c.v.-administered mouse leptin in rats and to assess the effects on meal pa tterns. Using a modified two-bottle paradigm we examined the putative avers ive response to i.c.v. doses of 1, 5, 7, 10, and 30 mu g of mouse leptin. A rtificial CSF and intraperitoneal lithium chloride served as negative and p ositive controls, respectively. Saccharin consumption in all leptin treatme nts was not significantly different from the negative control. Following a recovery period, rats from the same group were used to assess the effects o f a 30-mu g i.c.v. dose on cumulative food intake and meal patterns using a computer-based system for acquisition of feeding data. Leptin (i.c.v.) sig nificantly increased intermeal interval and decreased meal size. We, theref ore, conclude that mouse leptin, at doses up to 30 mu g i.c.v., is not aver sive in the rat, and that leptin has a multiphasic effect on meal patterns. (C) 1998 Elsevier Science Inc.