Galanin and the galanin antagonist M40 do not change fat intake in a fat- chow choice paradigm in rats

The neuropeptide galanin has been proposed to play a role in the regulation of fat intake. The purpose of the present investigation was to determine if galanin and the galanin receptor antagonist M40 would have selective effects on fat intake in a fat-chow choice paradigm in rats. Rats were adapted to 22-h access to chow alone and 2-h daily access to separate sources of fat and chow in the early dark cycle. Galanin (300 pmol, 1 nmol) or M40 (2-500 pmol) was microinjected bilaterally into the paraventricular nucleus of the hypothalamus (PVN) before the 2-h choice period, and chow and fat intake were measured. M40 had no effect on chow or fat intake. Galanin stimulated chow intake and increased the ratio of chow to fat consumed but had no significant effect on fat intake alone. These results suggest that endogenous galanin in the PVN may not play a primary role in the regulation of fat intake when fat is available in addition to a nutritionally balanced diet.