DOPAMINE ANTAGONISTS ACT ON CENTRAL, BUT NOT PERIPHERAL, RECEPTORS TOINHIBIT SHAM AND REAL FEEDING

We examined the relative contribution of dopamine (DA) receptors in th e brain and periphery in the control of sham and real feeding of sucro se solutions. Intraperitoneal (IP) administration of pimozide, an anta gonist of peripheral and brain DA receptors, suppressed both sham and real feeding in a dose-related manner. In contrast, IP injections of d omperidone, a DA antagonist restricted to peripheral receptors, had no effect on either sham or real feeding. The inability of domperidone t o influence sucrose intake did not result from a lack of biological ac tivity of the drug because the identical doses of domperidone that fai led to alter eating significantly inhibited gastric acid secretion. Th e results implicate central, but not-peripheral, DA receptors in the c ontrol of the ingestion of palatable foods and also suggest that sham feeding is more sensitive to DA antagonism than real feeding.