In vitro gallbladder motility in patients with radiolucent and radiopaque stones.

Twenty-five gallbladders were studied in vitro. Sixteen had radiolucent gallstones and 9 had radiopaque gallstones. The radiolucent gallstones had a cholesterol content of 94.17 +/- 3.76% and the radiopaque gallstones had a cholesterol content of 56.6 +/- 4.46%. Half the maximal response (ED50) to cholecystokinin octapeptide (CCK-OP) and to carbachol in strips from patients with radiolucent gallstones was 0.8 +/- 0.15 and 27.01 +/- 3.74 x 10(-7) M, respectively. In strips from patients with radiopaque gallstones, the ED50 was 0.4 +/- 0.08 and 14.92 +/- 3.07 x 10(-7) M, respectively. The ED50 values to CCK-OP and carbachol were greater in strips from specimens with radiolucent gallstones than in strips from specimens with radiopaque gallstones (p less than 0.05). There was no significant difference in the maximal contractile response of the two groups. It can be concluded that gallbladder sensitivity to CCK-OP and carbachol can be modified in relation to differences in the cholesterol and calcium content of the stones.