Onaka T, Yagi K
Department of Physiology, Jichi Medical School, Japan.
J Neuroendocrinol. 1998 Apr;10(4):309-16. doi: 10.1046/j.1365-2826.1998.00209.x.
Intravenously administered cholecystokinin octapeptide (CCK) induces oxytocin release from the neurohypophysis in anaesthetised rats. Memory of conditioned taste aversion can be acquired under anaesthesia. The present experiments aimed at investigating whether taste stimuli previously paired with i.v. CCK evoke oxytocin release from the neurohypophysis in urethane-anaesthetised male rats. Sucrose solution (0.75-2.0 M) paired with i.v. CCK or the vehicle was applied to the tongue. After 3 h, sucrose solution was applied again. The second sucrose slightly increased plasma oxytocin concentration in rats that had received the first sucrose solution paired with the vehicle. Plasma oxytocin concentration after the second sucrose application, however, was significantly higher in CCK-injected than in vehicle-injected rats. In rats that received CCK 1 h before the first sucrose application, a second sucrose application did not produce the oxytocin response. The magnitude of the oxytocin response to the second sucrose solution was increased in a manner related to CCK doses. In separate experiments, NaCl solution (0.75 M) paired with CCK or the vehicle was applied to the tongue. The second NaCl solution applied 3 h after the first one facilitated oxytocin release both in the rats that had received CCK or the vehicle. The increase in plasma oxytocin, however, was significantly larger in CCK than in vehicle-injected rats. In rats that had received the first sucrose solution paired with CCK, a second sucrose solution evoked a significantly larger increase in plasma oxytocin concentrations than a testing NaCl solution did. In rats that had received NaCl solution paired with CCK, a testing sucrose solution did not significantly change plasma oxytocin concentrations. These data suggest that the taste stimulus previously paired with i.v. CCK induces oxytocin release from the neurohypophysis in urethane-anaesthetised rats.
静脉注射胆囊收缩素八肽（CCK）可诱导麻醉大鼠神经垂体释放催产素。条件性味觉厌恶记忆可在麻醉状态下形成。本实验旨在研究先前与静脉注射CCK配对的味觉刺激是否能诱发氨基甲酸乙酯麻醉的雄性大鼠神经垂体释放催产素。将与静脉注射CCK或溶剂配对的蔗糖溶液（0.75 - 2.0 M）涂抹于舌部。3小时后，再次涂抹蔗糖溶液。第二次涂抹蔗糖后，接受首次与溶剂配对的蔗糖溶液的大鼠血浆催产素浓度略有升高。然而，注射CCK的大鼠在第二次涂抹蔗糖后血浆催产素浓度显著高于注射溶剂的大鼠。在首次涂抹蔗糖前1小时接受CCK注射的大鼠中，第二次涂抹蔗糖并未产生催产素反应。催产素对第二次蔗糖溶液反应的幅度随CCK剂量增加而增大。在单独实验中，将与CCK或溶剂配对的氯化钠溶液（0.75 M）涂抹于舌部。首次涂抹后3小时再次涂抹的氯化钠溶液在接受CCK或溶剂注射的大鼠中均促进了催产素释放。然而，注射CCK的大鼠血浆催产素升高幅度显著大于注射溶剂的大鼠。在接受首次与CCK配对的蔗糖溶液的大鼠中，第二次蔗糖溶液诱发的血浆催产素浓度升高显著大于测试用氯化钠溶液。在接受与CCK配对的氯化钠溶液的大鼠中，测试用蔗糖溶液并未显著改变血浆催产素浓度。这些数据表明，先前与静脉注射CCK配对的味觉刺激可诱导氨基甲酸乙酯麻醉大鼠的神经垂体释放催产素。
