Abstracts - Association for Chemoreception Sciences

P O S T E R S
#P275 POSTER SESSION VI:
PERIPHERAL AND CENTRAL TASTE;
PERIPHERAL OLFACTION
Diminished Fat Preference in Preprodynorphin KO Mice
Sharif A. Taha, Jennifer A. Heckmann, Bilal Shahid, Lara Kapp
University of Utah School of Medicine Salt Lake City, UT, USA
Opioid signaling plays an important role in modulating taste
reward. Signaling through kappa opioid receptors (KOR)
increases palatable food intake, while blockade of these receptors
attenuates consumption, implicating endogenous KOR signaling
in taste-guided behaviors. Competing hypotheses have proposed
that opioids increase intake of preferred tastants or, instead,
preferentially increase consumption of fat. Presently the role of
endogenous KOR ligands in taste-guided behaviors is poorly
understood. To understand the contribution of dynorphin
(the primary endogenous KOR ligand) signaling to taste
processing, we have systematically investigated tastant intake in
preprodynorphin KO and WT mice during 48 hour two bottle
choice experiments using sweet (saccharin, 0.1 – 100 mM; and
sucrose, 0.01-1 M), and fatty tastants (olestra, 0.16-10%; and
intralipid, 0.03-10%). To elucidate the contribution of
dynorphinergic signaling to fat preference, we performed
additional two bottle choice experiments in which sweet and fatty
taste options were presented simultaneously (sucrose [3-300 mM]
vs. intralipid [0.4, 0.8%] and saccharin [0.1-3 mM] vs. olestra [2.5,
5%]). Intake of fatty tastants was significantly lower for KO mice
relative to WT mice for both caloric (intralipid; main effect of
genotype, p=0.01) and non-caloric lipids (olestra; main effect of
genotype, p=0.04). In contrast, KO mice did not differ from WT
mice in overall levels of sweet tastant consumption (all p>0.05).
When fat vs. sweet preferences were tested directly, preference in
KOs for non-caloric tastants was significantly shifted toward
sweet and away from fat tastants (main effect of genotype for
preference, p=0.001, and olestra intake, p≤0.01). When tested with
caloric tastants, KO mice consumed significantly less lipid than
WT mice (p