Role of extrinsic and intrinsic nerves in the relationship between intestinal motility and transmural potential difference in the anesthetized ferret

Abstract

In the anesthetized ferret jejunum, the role of extrinsic and intrinsic nerves in the relationship between intestinal motor activity and transmural potential difference (PD) was studied. In the vagally intact ferret and after sympathetic blockade, spontaneous bursts of jejunal motor activity were associated with fluctuations in transmural PD. Both responses were abolished by vagotomy, atropine, and tetrodotoxin. Prolonged electrical stimulation of the cervical vagus nerve induced a cyclical motility pattern. Furthermore there was an initial rise in transmural PD which then plateaued, and superimposed on this were fluctuations in transmural PD. Atropine abolished the phasic pattern of motor activity and the fluctuations in transmural PD, although the tonic increase in transmural PD was not blocked. The results indicate that nervous activity, either spontaneous or induced, must be present for the cyclic fluctuations in transmural PD and motility. However, fluctuations in transmural PD associated with intestinal motility are not directly dependent on an intact vagal or sympathetic supply and involve coordination with the enteric nervous system.