Patterns meal- and caerulein-induced gallbladder emptying were compared in four dogs equipped with a strain gauge fixed on the gallbladder body and in four unoperated dogs. The maximum gallbladder dimensions according to X-Y-Z co-ordinates were measured ultrasonographically. Computation of gallbladder volume was based on the ellipsoid approximation method. Implantation of a strain gauge onto the gallbladder did not impair either its meal- or caerulein-evoked emptying. The dose of caerulein needed to induce gallbladder emptying to 50% of its basal volume amounted to 7.6 pmol.,kg-1,h-1, (95% confidence interval, CI: 6.4 - 9.0 pmol.,kg-1,h-1,) in unoperated dogs, and to 6.9 pmol.,kg-1,h-1, (95% CI: 6.0 - 7.9 pmol.,kg-1,h-1,) in dogs bearing a strain gauge on their gallbladders. After withdrawal of caerulein infusion (7.4 pmol.,kg-1,h-1, for 1 hour) a delayed return of the diameter, length, and consequently volume of the contracted gallbladder to basal values was observed in the operated compared to unoperated dogs.It is concluded that implantation of a strain gauge onto the gallbladder body does not impair either the meal- or caerulein-induced canine gallbladder emptying. Refilling of the contracted gallbladder appears to be slower in dogs with a strain gauge fixed onto their gallbladder.

Keywords: Caerulein, Gallbladder Emptying, gallbladder filling, strain gauge, Ultrasonography