Vagal-central nervous system interactions modulate the feeding response to peripheral enterostatin

Enterostatin selectively inhibits the intake of dietary fat after both peripheral and central administration. We have investigated the role of the hepatic vagus nerve in modulating the peripheral response to enterostatin in Sprague-Dawley rats adapted to a high fat (HF) diet. Intraperitoneal (ip) enterostatin reduced intake of HF diet after overnight starvation. This response was abolished by selective vagal hepatic branch transection. Immunohistochemical techniques were used to identify the location of Fos protein in brain nuclei after ip enterostatin. Fos protein was evident in the nucleus tractus solitarius (NTS), parabrachial, paraventricular and supraoptic nuclei. The pattern of expression of Fos-like immunoreactivity differed from that induced by the lipoprivic agent beta-mercaptoacetate. Transection of the hepatic vagus blocked the central Fos responses to ip enterostatin. We conclude that afferent hepatic vagal nerve activity is required for the feeding response to peripheral enterostatin.