The pharmacological reactivity of an isolated circular smooth muscle strip of the rabbit common bile duct.

An in vitro isolated spiral strip of rabbit common bile duct was prepared and tested for its pharmacological reactivity. It was found to be a suitable preparation with a long lasting and stable sensitivity when exposed to various drugs. The pharmacological reactivity proved to vary along the common bile duct; the different portions (sphincteric, median and hepatic) displayed different activities to the various agonists and antagonists. The following receptors were identified in different sections: alpha and beta-adrenergic, muscarinic cholinergic, bradykinin, H1 and prostaglandin F2 alpha. Only the sphinteric portion exhibited rhythmic peristalsis; the other portions produced merely small, irregular spontaneous contractions.