Abstracts - Association for Chemoreception Sciences

#P17 POSTER SESSION I: TASTE IMAGING &
PSYCHOPHYSICS; CENTRAL TASTE;
MULTIPLE MODALITIES; CENTRAL &
PERIPHERAL OLFACTION
Parabrachial taste responses to sucrose, fructose and Polycose
in the rat
Carolyn E. Pritchett, Peter Kovacs, Andras Hajnal
Department of Neural & Behavioral Sciences, Penn State
University, College of Medicine Hershey, PA, USA
Much attention has recently been given to the increase in sugars
in the modern diet, and their contribution to the current incidence
of obesity. Animals can distinguish between different types of
carbohydrates based on their oral effects, but how this
information is encoded within the central gustatory system
remains unknown. Therefore, we used extracellular single-unit
recording in the pontine parabrachial nucleus in anesthetized rats
while stimulating the anterior tongue with various concentrations
of sucrose (0.1-1.0 M), fructose (0.1-1.0 M) and Polycose ®
(0.02 and 0.2 M). Of the 56 taste responsive neurons recorded 46
(82%), 41 (73%), and 41 (73%) responded to sucrose, fructose,
and Polycose, respectively. All sucrose (S)-best neurons also
responded to fructose. In contrast, none of the S-best neurons
responded to Polycose while twice as many citric acid (CA)-best
neurons responded to only Polycose, compared to only sucrose
(12% vs. 6%), 75% of CA-best neurons responded to both.
Conversely, 3% vs. 11% of NaCl (N)-best units responded to
only Polycose or sucrose, respectively, whereas 72% of neurons
responded to both. Furthermore, sucrose was a more potent
stimuli than fructose at 0.1 M (neuronal responses corrected to
water baseline, spike/s mean ± S.E.: 4.75 ± 0.58 vs. 1.825 ± 0.75,
P