Effect of long-acting somatostatin analogue (octreotide, SMS 201-995) plus calcium channel blocker (Verapamil) on gallbladder contraction

BACKGROUND/AIMS: In this study we investigated the effect of the long-acting somatostatin analog octreotide (SMS 201-995) plus calcium channel blocker (Verapamil) on gallbladder contraction. METHODOLOGY: Fourty healthy volunteers participated in this study. Gallbladder volumes were measured by ultrasonography. After recording the baseline measurement;, the volunteers received either saline (n:10), or SMS 201-995 100 B mu g subcutaneously (sc.) (n:10) or verapamil 80 mg peroral (po) (n:10), or verapamil plus SMS 201-995 (n:10). Two hours later the gallbladder volumes were rescanned in 15 min intervals for 60 min. At the end all volunteers received standard liquid test meal (ensure 250 Cal/250 ml) and scans were again performed for one hour. RESULTS: The mean baseline gallbladder volume was 18.6+/-5.2 ml in all groups. The gallbladder volumes in the placebo group were 18.6+/-5.2 to 19.0+/-10.2 ml. In this group, after administration of test meal decreased the mean gallbladder volume to 14.3+/-7.5 to 8.4+/-5.8 ml, but these values were not significantly different from the baseline values. In the verapamil group the volumes increased from 18.6+/-5.2 to 28.5+/-9.7 to 30.8+/-11.6 ml. These values were significantly different from the baseline and the control group (p<0.05). In this group, postprandial mean volumes decreased to baseline in 30 min, but these values were higher than in the placebo group (p<0.01). Verapamil-induced fasting the gallbladder relaxation was totally abolished to the placebo value by SMS 201-995. In verapamil plus SMS 201-995 and SMS 201-995 alone groups, the fasting and post-prandial volumes did not change when compared to the baseline value, but post-prandial volumes were higher than the placebo (p<0.01). CONCLUSION: These results suggest that verapamil-induced gallbladder relaxation was totally abolished by SMS 201-995.