CHOLINERGIC DEPENDENCY OF STIMULATORY EFFECTS OF NEUROTENSIN ON EXOCRINE PANCREAS IN RATS

The biological activities of neurotensin, a 13-residue peptide, on the exocrine pancreas were examined in vitro using dispersed pancreatic a cini and in vivo using conscious rats. Neurotensin had weak amylase st imulatory activity in vitro, but its injection at 0.6 or 2 nmol/kg/h s timulated pancreatic exocrine secretion in vivo. CR-1409, a cholecysto kinin (CCK) receptor antagonist, partially inhibited neurotensin-stimu lated pancreatic secretion, although neurotensin did not stimulate pla sma CCK release. Atropine completely inhibited the pancreatic response to neurotensin. These results suggest that neurotensin has either a d irect biological action on the exocrine pancreas or an action mediated by cholinergic nerve transmission, and that neurotensin does not have a major physiological role in inducing pancreatic secretion.