BOMBESIN AND CHOLECYSTOKININ DIFFERENTIALLY AFFECT INGESTIVE MICROSTRUCTURAL VARIABLES WHETHER GIVEN ALONE OR IN COMBINATION

The ability of dose combinations of cholecystokinin (CCK) and bombesin to inhibit liquid glucose (0.125 gm/ml) intake and affect microstruct ural components of ingestive behavior in rats was examined. Five minut es before access to the glucose solution, rats were injected with dose pairs of CCK and bombesin. Both CCK and bombesin inhibited intake in a dose-related fashion. The magnitude of the inhibition produced by do se combinations was never greater than the sum of the inhibitions prod uced by the individual doses. CCK and bombesin affected different micr ostructural components of ingestion. CCK reduced burst size and cluste r size, whereas bombesin reduced burst number and cluster number. Thes e effects of the 2 peptides were not altered by the presence of the ot her peptide. These results suggest that different mechanisms of action underlie the feeding inhibitory actions of the 2 peptides.