CholecystokininB receptor antagonist increases food intake in rats

To investigate the role of cholecystokininB (CCKB) receptors in the brain in the control of food intake, we administered PD-135158, a specific and potent CCKB antagonist, into the lateral ventricle of male, Sprague-Dawley rats 30 min before a 60-min intake test. PD-135158 (0.001-0.5 mg) increased intake significantly; the mean peak increase was 39% more than the intake after vehicle treatment. The increased intake was due to a larger first meal and more intake during the last 30 min of the test. Because intake during the first 3 min, a measure of palatability or orosensory stimulation did not change significantly, we suggest that antagonism of brain CCK at central CCKB receptors decreased the satiating potency of the ingested food during the meal and decreased the potency of the mechanisms that prevent the reinitiation of eating during the postprandial intermeal interval.