The mode of action of intravenous pentagastrin injections on forestomach motility of sheep.

The investigation involved the recording of pressure changes in the reticulum and rumen of sheep. Rapid, intravenous injection of pentagastrin (0.2-1.0 microgram/kg body wt.) inhibited motility during eating and rumination as well as in sheep at rest. In anaesthetized sheep, after bilateral cervical vagotomy, contractions of the reticulum and rumen produced by stimulation of the vagus nerve were not prevented by pentagastrin injections (0.2-1.0 microgram/kg body wt.). In anaesthetized sheep with the left vagus nerve intact, stimulation of the central end of the right vagus nerve failed to elicit reflex contractions of the reticulum for 210-390 s after the intravenous injection of pentagastrin (0.6-0.7 microgram/kg body wt.).