Expression Of The Cβ Catalytic Subunit Of Camp-dependent Protein Kinase In The Anterior Thalami Nucleus Of The Rat During Learning And Memory

Objective: Anterior thalamic nucleus,the important contacting nuclei located inthe anterior of the dorsal thalamus of diencephalon, is an important part of the Papezcircuit, which is composed of three sub nuclear: anterior thalamic nucleus dorsalnucleus (AD), anterior thalamic nucleus ventralis nucleus (AV) and anterior thalamicnucleus medial nucleus (AM).It has been proved that the anterior thalamic nucleusdorsal nucleus and the anterior thalamic nucleus ventralis nucleus plays a positive rolein the process of learning and memory, but the mechanism of their participation in thestudy of learning and memory is known few. This study aims to investigate the possiblerole of the Cβ catalytic subunit of cAMP-dependent protein kinase (PKA-Cβ) in theanterior thalamic nucleus’ participation in learning and memory and further reveal therelated molecular mechanism of anterior thalamic nucleus participating in learning andmemory through observing the expression of PKA-Cβ in the anterior thalamic nuclei ofthe rats with Morris water maze training by using immunohistochemical technique.Methods: In the experiment30adult male Wistar rats which weight200-250gwere randomly assigned to experimental group and control group. The experimentalgroup were trained with Morris water maze experiment in5days to model spatialmemory formation, the control group was given the same conditions of theenvironmental stimuli but was not given the learning and memory training. On the fifthday the rats were given the perfusion of the heart using4%paraformaldehyde fixationwithin two hours after the space probe trial, then the brain was got and fixed at4°Covernight. The next day we observe the expression and distribution of PKA-Cβ in theanterior thalamic nuclei using the immunohistochemical staining method, and then doing the photomicrograph parallel and the image analysis. The data of the Morris watermaze behavior training and the photos analysis data are used SPSS software for thesingle factor analysis of variance. The data was evaluated for statistical significancewhen P＜0.05.Results: In the Morris water maze experiment, the escape latency of theexperimental group rats with the third day’s and fifth day’s training test and sixth day’sspatial probe test are used for data analysis, finding the escape latency of the fifth day’straining compared to shorten the third day’s (P<0.05) and no significant difference inthe escape latency of the fifth days’ training and the sixth days’ test. In theimmunohistochemical staining through light microscope, the expression of PKA-Cβwas located within the nucleus and nerve fibers, especially obvious in the anteriorthalamic nuclei of the rats in experimental groups microscope. Through the analysis ofthe average optical density of the positive expression, the experimental group washigher than that in the control group (P<0.05); in the experimental group, the expressionof AD zone is lower than the AV zone (P<0.05); in the control group, the differencesbetween AD zone and AV zone were not significant (P>0.05)Conclusion: In the process of learning and memory, the expression of PKA-Cβ inanterior thalamic nuclei of the rats was increased, which indicate that PKA-Cβ is relatedwith the mechanism of the ATN’s participating in spatial learning and memory.