Direct determination of the contractility of the XXXX gallbladder: a new in vivo model.

@entity1085 @entity575 @entity840 @entity8586 @entity10257
In vivo methods to study gallbladder contractility either equate gallbladder emptying with contraction or have relied on changes in gallbladder intravesicular pressure to reflect active transmural tension. We therefore devised an animal model in which the contractile force of the intact gallbladder is measured directly while the blood and neural supply remains uncompromised. Under general anesthesia one pole of the @entity840 gallbladder is anchored to the sternum and the other connected to a force displacement transducer. Any contraction--relaxation between these two points is recorded. This model was validated by measuring gallbladder response to both neuronal and humoral stimulation. Nerve stimulation was accomplished by means of two @entity575 collar electrodes placed in contact with the cystic duct. With nerve stimulation, a frequency (0.5-10 Hz) or amplitude (1-10 V) dependent contraction occurred. Intravenous @entity10257 (10 X 10(4) ng . kg-1 . h-1) and @entity8586 (3 X 10(4) ng . kg-1 . h-1) both induced dose-dependent @entity1085 . This model should prove useful in assessing the physiologic control of @entity1085 .
