AJP - Regulatory, Integrative and Comparative Physiology, Vol 263, Issue 5 1013-R1017, Copyright © 1992 by American Physiological Society
Duodenal preabsorptive origin of gustatory alliesthesia in rats
M. Cabanac and L. Lafrance
Department of Physiology, Laval University, Quebec, Canada.
Facial consummatory responses reflecting ingestive and aversive perceptions
were studied and quantified in rats chronically implanted with gastric,
duodenal, and oral catheters. A gustatory stimulus of 50 microliters of
1.75 mol/l sucrose was injected into the mouth every 5 min for 65 min. At
time 0, 0.5 ml containing 0.3 g glucose was injected into the stomach or
into the duodenum. Typical ingestive facial consummatory responses were
observed in response to sweet stimuli prior to the load. Aversive
consummatory responses were observed in response to sweet stimuli after the
glucose duodenal load (negative alliesthesia). The gastric load of glucose
was not followed by negative alliesthesia in response to sweet oral
stimuli. In the last part of the experiment the rats were vagotomized. When
the rats were subjected again to the same gustatory sessions, the duodenal
load was followed by weak and delayed negative alliesthesia in response to
sweet stimuli. These results in rats parallel results obtained in human
subjects and reinforce the hypothesis of the existence of a duodenal
preabsorptive signal for alimentary alliesthesia. They also suggest that
the vagus nerve plays a part in the perception of satiety.
