Oroesophageal factors in the patterning of drinking.

Eleven albino rats were fitted with chronic gastric fistulas to determine the effect of stomach draining on the pattern of drinking. Each animal was given ten two-hr drinking tests with the gastric fistula open on every other test. On the first open fistula test intake was five times greater than that of the following closed fistula test. However, the first fistula opening did not alter the temporal position of the first pause in intake. Across subsequent open, but not closed fistula tests, consumption increased further so that on the last test open fistula intake was ten times greater than in closed fistula intake. On the basis of these results it is suggested that the early portion of the drinking sequence is under the control of conditioned oroesophageal stimuli while the later phases of the sequence are controlled by stimuli arising from the alimentary canal and/or blood.