Intracerebroventricular injection of CCK reduces operant sugar intake in pigs

Pigs have a strong appetite for sugar solutions and readily learn to perform operant responses (pressing a panel with their snouts) to obtain glucose solution. Intracerebroventricular (ICV) injection of 1 microgram CCK produced a significant (p < 0.01) reduction in the amount of glucose consumed compared with saline in the 30 min following injection. The reduction was a central effect as the same dose of CCK was ineffective given intravenously. The inhibition of intake was completely abolished by prior dosing with 100 micrograms of the CCKA receptor antagonist Devazepide given ICV. Devazepide itself had no effect on intake. The pig is a good experimental animal for the study of the regulation of sugar intake.