Arris & Gale lecture. Regulation and responses of gallbladder muscle activity in health and disease.

A complex relationship links biliary symptoms with the mechanisms of gallbladder emptying and the presence of gallstones. This relationship has been investigated by clinical studies of symptoms associated with gallstones, by investigation of gallbladder emptying and cholecystokinin (CCK) release in patients with gallstones, and after cholecystectomy, or truncal vagotomy, and in the irritable bowel syndrome (IBS). Laboratory studies examined receptor density on bovine gallbladder, and contractility of human gallbladder in response to a variety of stimuli was studied in vitro. A set of six symptoms associated with the presence of gallstones was identified; IBS appeared to be present in two-fifths of patients before cholecystectomy but only one-third of these patients had persistent IBS symptoms one year after operation. Gallbladder emptying studies confirmed the poor contraction of stone-bearing gallbladders; abnormal patterns of emptying were also found in patients with IBS. Gallbladder emptying and filling appear to be largely neurally regulated. CCK receptor density was very low in gallbladder tissue, suggesting that receptors on nerve cells might mediate the action of CCK. Relaxation of gallbladder muscle was mediated by adrenergic and nitrergic nerves. The inflammatory mediator bradykinin, however, had a strong direct action on muscle cells to cause gallbladder contraction. The work reported here gives an overview of the symptoms and mechanisms of disease associated with the presence of stones in the gallbladder.