Vagal influence on cholecystokinin and neurotensin release in conscious dogs.

Cholecystokinin (CCK) release in seven conscious dogs was investigated by means of modified sham feeding. After sham feeding mean CCK concentrations rose from a basal value of 1.0 +/- 0.2 pmol/l to a peak value of 2.4 +/- 0.3 pmol/l (p less than 0.005). The release in response to sham feeding amounted to half of that seen after normal feeding. Atropine significantly altered CCK output after sham feeding (basal, 1.0 +/- 0.2 pmol/l; peak 1.3 +/- 0.3 pmol/l). Sham feeding did not affect neurotensin release. It is concluded that an important cephalic phase of CCK release exists which seems to be dependent on a cholinergic mechanism.