The role of brain-gut peptides in the control of sodium appetite.

Ingestion of food and fluid stimulates release of a number of peptides from the gastrointestinal system. These peptides are recognized to act as neurotransmitters/neuromodulators and act at both peripheral and central receptors. Many studies indicate that these peptides are important signals in terminating meals. Recent studies suggest that bombesin, a peptide related to gastrin-releasing peptide, suppresses sodium appetite. We have investigated the role of cholecystokinin (CCK) in the control of sodium appetite. Our studies indicate that CCK is effective at reducing saline intake. We found that exogenous, intraperitoneal CCK octapeptide suppresses saline intake. Moreover, administration of trypsin inhibitor to stimulate endogenous CCK release resulted in suppression of saline intake. Finally, intraperitoneal administration of the CCK receptor antagonist lorglumide resulted in increased saline intake. These observations extend the potential role of gastrointestinal peptides in the modulation of ingestive behavior.