The Study Of APP/PS1 Transgenic Mice's Behavior And Aβ Deposition, Connexin36, Connxin45

The formation of the senile plaques deposition ofβamyloid protein (Aβ) is the major pathological change in Alzheimer's disease (AD) and the decreased abilities of learning and memory are their main behavioral change. To study the effect of the senile plaques on the learning and memory, B6C3 APP /PS1 double transgenic mice aged 1.5, 3, 4.5 and 6-8 months were used and the same aged wild type B6C3 mice were used as the control experiment in the research. Morris water maze was used to test the abilities of learning and memory of the AD and control mice at different ages, and immunohistochemistry was used to examine the pathological change of senile plaques in the hippocampus. The relationship of the pathological change of the senile plagues with the abilities of learning and memory in the brain of AD model mice was considered. The results showed that, at behavioral level, the abilities of AD mice's learning and memory of 1.5, 3 and 4.5 months did not show distinctive difference compared with the control group at the same age ( P> 0.05) , while the abilities of AD mice of 6-8 months were significantly lower than the control group of the same age ( P < 0.01) . At morphological level, there were only a few plaques in the hippocampus of the AD mice of 4.5 months, while the plaques were significantly increased both in number and volume in the hippocampus of AD mice of 6-8 months. These results suggest that the behavioral change were affected by the formation of the senile plaques.Gap junction are present in almost all cell types of vertebrate organisms, and, in the nervous system, electrical synapse is an important pathway of communications between neurons. Connexin36 (Cx36) and connexin45 (Cx45) were found in certain neurons of the central nervous system. The hippocampus is associated with the abilities of learning and memory, emotional behavior and epilepsy. There was reported that the Cx36 gene knockout mice were injured in learning and memory. In this experiment, Cx36 and Cx45 APP / PS1 double transgenic mice were observed in CA3/CA4 of the hippocampus by immunohistochemistry. And, the two proteins were distributed in the hipppcampal pyramidal cell's membrane, the results suggested that Cx36 and Cx45 involved in the hippocampal pyramidal cell's electrical synapses. This article provides a basis for the research of the signal transduction, signal coding, signal modulation and integration of hippocampus and its role in learning, memory, emotion and behavior, and, for the further study of the impact of Aβdeposition on hippocampal neuronal injury and neuronal synapse.