A neuroendocrinological study on the mechanism of activation of neurotransmitter by mastication

观察咀嚼对大鼠学习记忆的影响。获得以下结果。(1)在Hebb和威廉姆斯迷宫实验中，将24只Wistar大鼠分为四组：正常固体餐组（Solid Rats）、液体餐组（Liquid Rats）、颈静脉高营养组（IH Rats）和胃贲门部液体餐组（LMI Rats）。固体大鼠的总错误分数显著低于液体大鼠。Liquid大鼠的总错误分数显著低于IH大鼠和LMI大鼠。IH大鼠和LMI大鼠之间的总错误分数没有显著差异。(2)测定上述大鼠下丘脑室旁核和弓状核神经肽Y（NPY）含量。固态大鼠血浆中NPY含量显著高于液态大鼠。液体大鼠血浆NPY含量显著高于IH和LMI大鼠。结果表明，经口进食，尤其是咀嚼进食，对大鼠学习能力的发育有重要作用，NPY参与了这一发育机制。

Effects of mastication were examined on the learning and memory in rats. The following result was obtained.(1) In Hebb and Williams' maze test, twenty-four Wistar rats were divided into four groups: rats which were fed normal solid meal (Solid Rats), liquid meal (Liquid Rats), intravenous hyperalimentation through jugular vein (IH Rats) or liquid meal infusion through cardiac part of stomach (LMI Rats). The total error score of the Solid Rats were significantly less than that of the Liquid Rats. The total error score of the Liquid Rats were significantly less than those of the IH Rats and the LMI Rats. There was no significant difference of the total error scores between IH Rat and LMI Rat.(2) Neuropeptide Y (NPY) concentrations in hypothalamus (paraventricular nucleus and arcuate nucleus) of the above-mentioned rats were measured. NPY concentration in Solid Rat was significantly higher than that in Liquid Rat. And NPY concentration in Liquid Rat was significantly higher than that in IH Rat and LMI Rat. There was no significant difference of NPY concentration between IH Rat and LMI Rat.These results suggest that food intake through mouth, particularly with mastication, is important for development of ability of learning in rats and that NPY is involved in this mechanism of development.