Vasoactive intestinal polypeptide stimulates cholecystokinin secretion in perfused rat duodenum.

We examined the effect of vasoactive intestinal polypeptide (VIP) on cholecystokinin (CCK) secretion from the isolated perfused rat duodenum. VIP stimulated CCK secretion mono-phasically in a concentration-dependent manner in concentrations ranging from 10(-9) to 10(-7) M, and 10(-7) M of VIP led to an increment of 82 +/- 25.8 fmole/3 min. The stimulatory effect of VIP on CCK was not inhibited by 10(-5) M atropine. These results suggest that VIP may directly stimulate CCK secretion from the duodenum and work as a non-cholinergic, peptidergic neurotransmitter.