Pentagastrin stimulates tonic and phasic contractile activity of the canine stomach

Seven strain gage force transducers were sutured in line to the stomach of an anesthetized dog. Quantification of tonic acitivity and of phasic activity (amplitude, frequency and propagation velocity) on 7 locations from fundus to pylorus resulted in an overall picture of gastric motor activity. Pentagastrin (dose-response curve, 1--8192 ng/kg, i.v.) did not change propagation velocity of the contractile waves, but increased the amplitude and frequency of phasic activity on corpus and antrum. Amplitude increased on the antrum more than on the corpus. Frequency increase was uniform over corpus and antrum. Moreover pentagastrin increased muscle tone (tonic activity) in a specific area on the corpus from 12--18 cm to pylorus. The distinct responses to pentagastrin of tonic activity and of amplitude and frequency of phasic activity indicate that pentagastrin acts on 3 different receptor-effector systems.