methylcellulose and lorglumide

The aim of the study was to examine the possible involvement of cholecystokinin (by lorglumide) and cholinergic mechanisms (by atropine) in magnesium sulphate (MgSO(4))-induced gallbladder contraction of conscious dogs. The gallbladder (GB) volume was determined by ultrasonography. The optimal dose of 80 mg kg(-1)of MgSO(4)was determined from a MgSO(4)dose-response curve using doses of 10, 20,40, 80, 120 mg kg(-1). The largest dose of MgSO(4)was less effective than the optimal dose. Peak gallbladder contraction (32 per cent) was achieved at 30 minutes. Atropine (50 microg kg(-1)s.c.) or lorglumide (1 mg kg(-1)p.o.) fully prevented GB contraction. In conclusion, supraoptimal doses of MgSO(4)have a diminishing effect. The sustained contraction of the gallbladder in response to the optimal dose of MgSO(4)can be explained by an additive effect of the cholecystokinin release and a cholinergic trigger mechanism. Ultrasonography and MgSO(4)stimulation proved to be a valuable technique for examination of gallbladder motility.

Topics: Animals; Atropine; Cholecystokinin; Dogs; Dose-Response Relationship, Drug; Drug Interactions; Female; Gallbladder; Hormone Antagonists; Magnesium Sulfate; Methylcellulose; Muscarinic Antagonists; Muscle Contraction; Proglumide; Ultrasonography