Inhibition of exocrine pancreatic secretion by alpha-adrenergic blocking agents in conscious rats.
The effects of the alpha-adrenergic blocking agents, phentolamine and phenoxybenzamine were tested on the exocrine pancreatic secretion of conscious rats. Phentolamine (0.156 mg/kg to 1.25 mg/kg) and phenoxybenzamine (1.25 and 2.5 mg/kg) strongly inhibited basal volume and protein secretion. On the other hand, phentolamine had no effect on the cholecystokinin-pancreozymin or urecholine stimulated exocrine pancreatic  secretion. The infusion of phentolamine (1.25 mg/kg/hr) greatly impaired the stimulatory effect on protein secretion induced by soybean trypsin inhibitor and oleic acid. These experiments suggest that alpha-adrenergic blocking agents inhibit pancreatic secretion of the conscious rat by impairment of cholecystokinin-pancreozymin release either by a direct inhibitory action or by blocking a still unknown alpha-adrenergic stimulatory reflex present in the duodenal mucosa.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D002766:Cholecystokinin / Q000494:pharmacology; D003864:Depression, Chemical; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010643:Phenoxybenzamine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D051381:Rats; D012633:Secretin / Q000494:pharmacology; D013997:Time Factors
D000317:Adrenergic alpha-Antagonists; D011506:Proteins; D010643:Phenoxybenzamine; D012633:Secretin; D002766:Cholecystokinin; D010646:Phentolamine