Blockade of bombesin receptors with [Leu14-psi(CH2NH)-Leu13]bombesin fails to suppress nutrient-induced CCK release from rat duodenojejunum.
The present study was undertaken in order to delineate the contribution of enteric bombesin (BBS)-containing nerves in the food-induced release of intestinal cholecystokinin (CCK). For this purpose, the isolated vascularly perfused rat duodenojejunum model was used and the new compound [Leu14-psi(CH2NH)-Leu13]BBS was infused intraarterially at a concentration of 10(-6) M to block the BBS receptors. Vascular infusion of BBS alone (10(-8) M or 10(-9) M) provoked a dose-dependent release of CCK-like immunoreactivity (CCK-LI). The secretion pattern of CCK was biphasic and consisted of a transient peak (300-400% above basal) followed by a sustained response (200-300% above basal). Vascular coinfusion of the BBS analogue with BBS 10(-9) M completely abolished both phases of CCK release while only the second phase of CCK secretion was profoundly reduced upon coadministration of BBS 10(-8) M with the BBS receptor antagonist. Luminal administration of mixed nutrients induced a prompt and well-sustained release of CCK-LI which was unaffected upon arterial infusion of the BBS analogue. These data suggest that the intestinal supply in BBS-producing nerves is not involved in the food-induced release of intestinal CCK in the rat.
Cuber
J C
JC
INSERM U45, Hôpital E. Herriot, Lyon, France.
Bernard
G
G
Coy
D H
DH
Bernard
C
C
Chayvialle
J A
JA
D000818:Animals; D001839:Bombesin / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D002766:Cholecystokinin / Q000378:metabolism*; D004032:Diet; D004386:Duodenum / Q000294:innervation / Q000378:metabolism*; D007583:Jejunum / Q000294:innervation / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter / Q000037:antagonists & inhibitors*
D018004:Receptors, Bombesin; D017981:Receptors, Neurotransmitter; C057644:bombesin, Leu(13)-psi-CH2NH-Leu(14)-; D002766:Cholecystokinin; D001839:Bombesin