Elsevier

Physiology & Behavior

Volume 66, Issue 5, July 1999, Pages 863-867
Physiology & Behavior

Articles
Hyperresponsiveness to Palatable and Aversive Taste Stimuli in Genetically Obese (Bombesin Receptor Subtype-3–Deficient) Mice

https://doi.org/10.1016/S0031-9384(99)00032-3Get rights and content

Abstract

Taste preference in obese mice was examined using genetically obese (bombesin receptor subtype-3: BRS-3–deficient) animals. Preference for either sodium saccharin (0.2%), sodium chloride (0.9%), citric acid (0.1%), or quinine sulfate (0.002%) solution was examined using a two-bottle test situation, and BRS-3–deficient mice not only showed a stronger preference for saccharin solution, but also a stronger aversive response to quinine solution, relative to wild-type littermates. Furthermore, a conditioned taste-aversion test measured the consumption of sodium saccharin (0.2%) and sodium chloride (0.9%) solutions after intraperitoneal injection of LiCl (0.3 M, 1 mg/kg), and BRS-3–deficient mice exhibited stronger aversion to both solutions than did control animals. In situ hybridization demonstrated that the BRS-3 gene is expressed in the parabrachial nucleus, the medial and central nuclei of the amygdala, and the hypothalamic nuclei such as paraventricular nucleus, all of which are known to be involved in taste perception. These results suggest that expression of the BRS-3 gene in these nuclei is important for the modulation of taste preference, as well as the development of obesity.

Section snippets

Breeding and experimental conditions

Breeding and all experiments were conducted in a temperature- and humidity-controlled room (23 ± 2°C, 60 ± 5%). The light–dark cycle was 12:12 (lights on at 0800 h). Mice were housed in ordinary plastic caging [190 × 260 × 125 (H) mm] with wood shavings. All mice were housed individually for at least 2 weeks before the beginning of the experiment. Ordinary laboratory chow (JCL Inc. CE-2, 342.2 kcal/100 g) and water were freely available to mice, unless specified otherwise. The following animal

Taste Preference Test

In the taste preference test, BRS-3–deficient mice not only showed greater preference for sodium saccharin relative to wild-type control mice (t = 2.89, p < 0.02, two-tailed), but also exhibited a lower preference for quinine sulfate (t = 2.81, p < 0.03, two-tailed; Fig. 1). Although BRS-3–deficient mice showed slightly greater preferences for both sodium chloride and citric acid than did wild-type mice, these differences were not statistically significant (t = 0.29, NS; t = 1.53, NS,

Discussion

In this study, we examined taste preference/aversion in BRS-3–deficient mice. In the taste preference test, BRS-3–deficient mice showed a stronger preference for sodium saccharin solution and a stronger aversive response to quinine sulfate solution when compared with wild-type mice. These results indicate that BRS-3–deficient mice exhibit greater responsiveness to the palatability of taste stimuli. Although BRS-3–deficient mice showed a strong preference for sodium saccharin but not for sodium

Acknowledgements

This work was supported in part by research grants from The Ministry of Education, Science, Sports and Culture, The Ministry of Health and Welfare, the Science and Technology of Japan, the Japan Health Science Foundation and the Japan Foundation for Neuroscience and Mental Health.

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