Modulation of Taste Reactivity by Intestinal Distension in Rats

• Published in: Physiology & behavior Vol. 66; no. 3; pp. 529 - 535
• Main Authors: Gyetvai, Beatrix, Bárdos, György
• Format: Journal Article
• Language: English
• Published: Cambridge Elsevier Inc 01.05.1999; New York, NY Elsevier
• Subjects: Anatomical correlates of behavior; Animals; Appetite Regulation - physiology; Appetitive Behavior - physiology; Behavioral psychophysiology; Biological and medical sciences; Cues; Dilatation; Fundamental and applied biological sciences. Psychology; Intestine, Small - physiology; Linear Models; Male; Mechanical stimuli discomfort; Models, Psychological; Pain; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rat; Rats; Rats, Long-Evans; Reinforcement (Psychology); Satiation - physiology; Sensation - physiology; Small intestine gut distension; Stress, Mechanical; Taste - physiology; Taste reactivity; Pain; Small intestine gut distension; Mechanical stimuli discomfort; Rat; Taste reactivity; Digestive system; Rodentia; Male; Small intestine; Vertebrata; Mammalia; Motivation; Animal; Gustation; Perception; Taste; Mechanical stimulus; Chemical stimulus
• ISSN: 0031-9384; 1873-507X
• DOI: 10.1016/S0031-9384(98)00319-9

Discomfort created by intestinal distension may play a role in controlling intake behavior. We analyzed these effects in details by the taste reactivity test in Long–Evans rats. A balloon inserted into a separated Thiry-Vella intestinal loop was distended with different volumes of water (0.05, 0.09, 0.12, and 0.28 mL, respectively). Saccharin solution (0.001 M) was infused into the mouth via an implanted oral cannula nine times for 30 s, with 5-min intertrial intervals. The balloon was distended after the second and released following the seventh trial. Taste reactivity (TR) elements were videotaped and later analyzed for appetitive and aversive responses. The number of appetitive responses decreased after gut distension, whereas aversive elements were unfrequent and stable. It is suggested that pleasantness of the taste stimulus decreased independently of the discomfort, which remained mild but steady; that is, sweet taste gradually lost its hedonic value but was not accompanied by an acquired aversion of the same taste. This finding may point to the difference of the motivational and discriminative effects of the internal stimuli.