乙酰胆碱对缺碘子代大鼠海马神经元单位放电活动的影响

Effects of Acetylcholine (ACh) on Spontaneous Unit Discharge of Hippocampal Neuron of Cretinism Rats

研究了缺碘子代大鼠海马神经元单位的自发放电活动,以及侧脑室注射乙酰胆碱(ACh)对海马神经元放电活动的影响。结果表明,与正常对照组比较,缺碘子代大鼠海马神经元单位自发放电活动的中频放电单位明显减少,侧脑室注射ACh后,发生兴奋的单位数也明显减少,发生兴奋的时相明显延迟。结果提示缺碘子代大鼠海马神经元放电活动异常既是胚胎期及新生期缺碘和甲状腺激素不足对海马神经元分化发育影响的结果,又是导致缺碘子代大鼠学习记忆力低下,条件反射不易形成与建立的病理生理学基础。

This experiment was designed to expound the mechanism and its significance of the unit discharge of HPC neuron and cholinergic activity of HPC in cretinism rats. This experiment was made on, with 53 control, ones 35 cretinism rats which suffered iodine deficience and hypothyroidism since their fetus period. 95 cretinism and 132 control spontaneous unit discharge units were recorded extracellularly with glass microelectrode in HPC.Some differences were found between the two groups. 27 experimental units and 47 control (?)nits were observed after intralateral cereberal ventrical (ICV) injection of ACh, and different reactions were found. Contract to the cont rol, the radio of excited unit decreased significantly (27.7% in normal, 7.4% in cretinism rat, P less than 0.01), and the uncharge units increased obviously (8 % in normal, 29% in cretinism rat, P less than 0.01). The onset of excited reaction in cretinism rats was delayed too. The results of the different reactions of HPC neuron unit discharge to ICV injection ACh indicatad the mechanical disorder of cholinergic neuron in cretinism rats. This disorder might result from the effect of ID and hypothyroidism on the development of HPC during the fetus, while it is an important basis of pathophysiology leading to poor learning and memory of cretinism ats.