| Research Abstract |
It is known that rats show the ingestive and/or aversive behaviors in response to intraorally administered taste solutions (Grill and Norgren, 1978). However, the effects of tastes on feeding behaviors are not well analyzed yet. In this study, food-deprived Wistar male rats test foods made up by mixing powdered chow with one of the liquids such as distillled water, 1M sucrose, 0.02M saccharin-Na, 0.2M NaCl, 20mM HCl, and 1mM or 5mM quinine-HCl. The behavioral study revealed that rats ate a smaller amount of food containing 5mM quinine-HCl with longer time than foods containing other tastes. Gaping, one of the aversive behaviors, was frequently observed when the rats ate food contaning quinine. In the EMG study, the activities of temporalis, masseter and digastric muscles were recorded. The magnitudes of burst discharges were smaller for quinine-adulterated food than for other foods. The masticatory cycle during eating quinine-adulterated food was faster than that for other foods. The resent study concludes that rats show altered eating behaviors, and masticatory EMG activities exclusively when they eat food with quinine taste.
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