Chemical Senses Advance Access originally published online on September 7, 2009
Chemical Senses 2009 34(8):685-694; doi:10.1093/chemse/bjp055
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Role of Olfaction in the Conditioned Sucrose Preference of Sweet-Ageusic T1R3 Knockout Mice
1 Department of Psychology, Brooklyn College of CUNY, 2900 Bedford Avenue, Brooklyn, NY, 11210, USA 2 Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104, USA
Correspondence to be sent to: Anthony Sclafani, PhD, Department of Psychology, Brooklyn College of CUNY, 2900 Bedford Ave, Brooklyn, NY 11210, USA. e-mail: ASclafani{at}gc.cuny.edu
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Abstract |
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Prior work has shown that sweet taste–deficient T1R3 knockout (KO) mice developed significant sucrose preferences when given long-term sugar versus water tests. The current study investigated the role of olfaction in this experience-conditioned sucrose preference. T1R3 KO and C57BL/6 wild-type (WT) mice were given 24-h sugar versus water tests with ascending concentrations of sucrose (0.5–32%), after which the mice received olfactory bulbectomy (OBx) or sham surgery. When retested with sucrose, the Sham-KO mice preferred all sugar solutions to water, although their intake and preference were less than those of the Sham-WT mice. The OBx-KO mice, in contrast, showed no or weak preferences for dilute sucrose solutions (0.5–8%) although they strongly preferred concentrated sugar solutions (16–32%). OBx-WT mice displayed only a partial reduction in their sucrose preference. Although the OBx mice of both genotypes underconsumed dilute sucrose solutions relative to Sham mice, they overconsumed concentrated sucrose. These results indicate that olfaction plays a critical role in the conditioned preference of T1R3 KO mice for dilute sugar solutions. Further, the fact that OBx-KO mice preferred concentrated sucrose solutions in the absence of normal sweet taste and olfactory sensations underscores the potency of postoral nutritive signals in promoting ingestion.
Key words: C57BL/6J mice, olfactory bulbectomy, postoral conditioning, preference, sucrose
Accepted 5 August 2009