Biol. Pharm. Bull. 28(7) 1291—1293 (2005)

by a series of neurobehavioral alterations such as depression of feeding, exploratory and sexual behaviors. Although the mechanism of the neurobehavioral alterations during peripheral inflammation are largely unknown, this process involves the generation of proinflammatory cytokines as well as prostaglandins, cyclooxygenase (COX) metabolites of arachidonic acid, in the peripheral tissues or central nervous systems. Our prevous investigation demostrated that dietary n-3 polyunsaturated fatty acids (PUFA) attenuated the reduction of food-motivated behavior and social exploration in the mice with systemic inflammation induced by lipopolysaccharide (LPS). It is known that dietary supplementation with n3 PUFA inhibits prostaglandins generation from arachidonic acid and modulates the synthesis of proinflammatory cytokines, which may explain the attenuation of the behavioral depression upon LPS administration. However, it has been not yet examined whether dietary n-3 PUFA attenuate the behaviroal depression under different inflammatiory conditions. Intraperitoneal injection of zymosan induces acute peritonitis in the experimental animals, which is associated with the increased vascular permeability and viceral pain response assessed as writhing. It is known that vasoactive and nociceptive prostaglandins generated locally contribute to these inflammatory reactions. In addition, zymosan-induced peritonitis is reported to be associated with behavioral depression such as the reduction of food intake. Although the role of inflammatory mediators involved in the behavioral depression during zymosan-induced peritonitis has not been investigated, it is possible that endogenous proinflammatory cytokines or prostaglandins also play an important role. In the present study we examined the effect of dietary n-3 PUFA on the reduction of food-motivated behavior as well as plasma leakage and writhing response during zymosan-induced peritonitis in mice. MATERIALS AND METHODS