Effects of mechanical loads of feeding on the physiological development of a central nervous system.

我们研究了咀嚼功的减少是否会影响中枢神经系统的电生理学生理特征。雄性大鼠，在3周龄断乳，无论是毛皮（SL）或粉末（PW）饲料喂养，直到4和10个月的年龄和电生理实验进行的每一个喂养组。在离体海马脑片上研究了学习记忆的长时程增强（LTP）和突触电位在Schaffer侧支（Sc）-CA 1通路中的作用。用离子电渗法研究了海马CA 1区锥体细胞顶树突上递质（GABA、谷氨酸）的敏感性。实验结果如下：（1）SL组和PW组锥体细胞膜电位无明显变化。(2)SL组的突触电位比PW组的突触电位具有更复杂的特征。(3)与PW相比，SL组中GABA和谷氨酸的树突状受体位点位于SL组中。(4)结果2和3表明，在SL组，神经元网络发育正常。这些结果可能表明，强有力的咀嚼运动促进了中枢神经系统的功能发育。

We have investigated whether a decrease in masticatory work affected the physiological characteristics of the central nervous system electrophysiologically. Male rats, weaned at 3 weeks of age, were fed either pelted (SL) or powdered (PW) chow until 4 and 10 months of age and electrophysiological experiments were performed on each of feeding groups. Long-term potentiation (LTP) to be believed as learning and memory and synaptic potential were studied in the Schaffer collateral (Sc) -CA1 pathway in an in vitro slice preparation of hippocampus. The sensitivity of transmitters (GABA,glutamate) on the apical dendrites of a pyramidal sell in CA1 was investigated iontophoretically. Experimental results were as follows : (1) Significant change of membrane potentials of the pyramidal cells was not observed between the SL and PW groups. (2) Synaptic potentials recorded from the SL.groups showed more complicated feature than the PW.(3) Dendritic receptor site for GABA and glutamate was localized in the SL group compared to the PW.(4) The amplitude of LTP recorded from the PW group was significantly bigger than from the SL.Results of 2 and 3 mean that in the SL group, neuronal networks develop normally. These results may suggest that strong masticatory works promote the functional development of the central nervous systems.