ABSTRACT
Following a meal, a cascade of events is initiated that results in the delivery of bile from the gallbladder to the lumen of the duodenum. An important messenger in the activation of this response, cholecystokinin, acts through neural mechanisms to increase pressure in the gallbladder and decrease resistance in the sphincter of Oddi, thus facilitating the flow of bile. Only recently have the neurons residing in the gallbladder and the sphincter of Oddi been directly studied to establish their morphological, electrical and neurochemical properties; the types of inputs that they receive; and how they respond to these signals. This chapter is organized to provide an overview of (1) the basic properties of gallbladder and sphincter of Oddi neurons, (2) the inputs to these cells that have been investigated, and (3) the reflex interactions that exist between the gut and the gallbladder, the gut and the sphincter of Oddi, and the gallbladder and the sphincter of Oddi. Although the neurons that migrate to, and ultimately innervate, the gallbladder and the sphincter of Oddi share a common ancestry with the neurons of the gut tube, the neurobiology of each of these regions is uniquely adapted to carry out their particular functions.
