The functional link between tail-pinch-induced food intake and emotionality and its possible role in stress coping in rats.

Tail pinch facilitates eating in rats. We investigated an unidentified link between tail-pinch-induced eating behavior and individual emotionality in male Sprague-Dawley rats. Anxiety-like behavior was assessed on the elevated plus maze (EPM) and in the open field test (OFT). Tail-pinch-induced eating was observed as follows: After a 30-min habituation period, the tail pinch was applied for 5 min, followed by a 30-min recovery period. During the habituation and recovery periods, rats were allowed to access food ad libitum. During the recovery period, 14 of 24 rats ate more food than during the habituation period. Thus, we named them "high responders" and the others as "low responders". The food intake was significantly greater, while the times spent in the open arms in the EPM and in the center area in the OFT were significantly shorter in high responders than in low responders. This result suggests that the rats consuming more food after mild stress have higher anxiety.

Suppression of Oral Sweet Taste Sensation with Gymnema sylvestre Affects Postprandial Gastrointestinal Blood Flow and Gastric Emptying in Humans.

An oral sweet taste sensation (OSTS) exaggerates digestive activation transiently, but whether it has a role after swallowing a meal is not known. Gymnema sylvestre (GS) can inhibit the OSTS in humans. We explored the effect of the OSTS of glucose intake on gastrointestinal blood flow, gastric emptying, blood-glucose, and plasma-insulin responses during the postprandial phase. Eight participants ingested 200 g (50 g × 4 times) of 15% glucose solution containing 100 mg of 13C-sodium acetate after rinsing with 25 mL of 2.5% roasted green tea (control) or 2.5% GS solution. During each protocol, gastrointestinal blood flow and gastric emptying were measured by ultrasonography and 13C-sodium acetate breath test, respectively. Decreased subjective sweet taste intensity was observed in all participants in the GS group. The time to attain a peak value of blood flow in the celiac artery and gastric emptying were delayed in the GS group compared with the control group. At the initial phase after glucose intake, blood-glucose and plasma-insulin responses were lower in the GS group than those for the control group. These results suggest that the OSTS itself has a substantial role in controlling postprandial gastrointestinal activities, which may affect subsequent glycemic metabolism.