Metoclopramide enhances bethanechol-induced pancreatic exocrine secretion of the dog.
The effects of metoclopramide on pancreatic exocrine secretion were investigated in the pentobarbitone-anaesthetized dog. All drugs were injected into the femoral vein. Metoclopramide (10-1000 micrograms/kg) did not change the resting rate of pancreatic secretion. Pancreatic secretion, induced by bethanechol (3 micrograms/kg), was dose-dependently enhanced by simultaneous injections of metoclopramide (10 and 30 micrograms/kg), but the protein and bicarbonate concentrations of the pancreatic juice were not affected. Secretions induced by secretin (0.1 units/kg) and dopamine (3 micrograms/kg) were not modified by metoclopramide at up to 30 micrograms/kg. A larger dose of metoclopramide (1000 micrograms/kg) suppressed dopamine-induced secretion to a lesser extent than the same dose of sulpiride. From these results, it is concluded that metoclopramide enhances secretory responses to cholinergic stimulations by peripherally sensitizing the muscarinic receptor-mediated exocrine process and this drug is a weaker antagonist of the dopamine D2 receptors than sulpiride.
Yamagishi
F
F
Haruta
K
K
Homma
N
N
Iwatsuki
K
K
Chiba
S
S
D000818:Animals; D018723:Bethanechol; D001626:Bethanechol Compounds / Q000494:pharmacology*; D001639:Bicarbonates / Q000378:metabolism; D004285:Dogs; D004298:Dopamine / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D007700:Kinetics; D008297:Male; D008787:Metoclopramide / Q000494:pharmacology*; D010179:Pancreas / Q000187:drug effects; D010189:Pancreatic Juice / Q000378:metabolism*; D012633:Secretin / Q000494:pharmacology
D001626:Bethanechol Compounds; D001639:Bicarbonates; D018723:Bethanechol; D012633:Secretin; D008787:Metoclopramide; D004298:Dopamine