There is no technique which gives direct information on the contraction of the human gall bladder in vivo.Methods which have been used, depending on radiology (Burton, Harper, Howat, Scott, and Varley, 1960), or on the aspiration of bile by duodenal intubation, show the gall bladder emptying, but emptying does not necessarily imply contraction of the gall bladder wall, since it also depends on the activity of the sphincter of Oddi and surrounding duodenal musculature. Thus the action of drugs on the bile duct sphincter mechanisms may well mask any action which they have on the muscle of the gall bladder itself. A calculus impacted in the neck of the gall bladder, with consequent obstruction of the cystic duct, is a common cause of biliary pain. It is usual to treat this pain with pethidine and atropine, although as has been indicated, we have no direct knowledge of the action of these drugs on the gall bladder muscle or even of the basic physiology of the tissue. The in vitro technique seems to be applicable to the investigation of this problem.The present study was undertaken in order to investigate the physiology and pharmacology of smooth muscle of the gall bladder. No such study appears to have been made previously, as the existing accounts have been derived from the indirect experimental techniques referred to above and by extrapolation from results obtained on lower animals. In vitro studies of isolated gall bladders or of strips of gall bladder wall have been mainly concerned with the dog and guinea pig which are technically suited to this method. Ravdin and Morrison (1931) did, however, study strips taken from the gall bladder of the Rhesus monkey. These authors also mention a single human gall bladder which contained multiple stones and whose wall was thickened by inflammatory change. Strips from the wall of this organ showed tone and spontaneous activity in an organ bath, but the authors did not examine the effect of added substances.
METHODSFifty strip preparations of human gall bladder from 25 specimens removed at operation were studied. Immediately after removal the unopened gall bladder was placed in Ringer lactate solution chilled to 4°C and gassed with 95% 02 and 5% CO2. Strips of the wall of the organ, containing muscle and mucosa, and about 20 mm by 2 mm, were cut within two hours of removal. In the majority of experiments a pair of strips were set up together in the same organ bath giving a simultaneous record of the circular and longitudinal muscle.The preparation was suspended in modified Krebs solution at 37°C equilibrated with the 95% 02 and 5 % CO2 mixture. Recordings were made on a smoked drum using an isotonic system with a load of IG. A vibrator was used to reduce friction.The modified Krebs solution was made up as follows (g/litre): NaCl 7-8, KCI 0.35, NaHCO3 1-37, NaH2PO4 0.165, CaCI2 0-28, MgC12 0-01, dextrose 1-4.The effect of the following pharmacologically active substances on the gall-bladder preparations was studied: acetylcholine chloride, physostigmine sulphate, atropine sulp...