Spatial learning alters hippocampal calcium/calmodulin-dependent protein kinase II activity in rats.
This study investigated the role of hippocampal CaM-kinase II (calcium/calmodulin-dependent protein kinase II) in spatial learning. In Experiment I, three groups of rats received 1, 2 or 5 days of training on a spatial task in the Morris water maze with a hidden platform, while a control group was trained on a nonspatial task with a visible platform. The acquisition rate in the spatial task was slower than that in the nonspatial task. However, rats receiving 5 days of spatial training had the highest Ca(2+)-independent activity of CaM-kinase II compared with the controls receiving nonspatial training and rats having 1 or 2 days of spatial training. Furthermore, the level of hippocampal Ca2+-independent CaM-kinase II activity was correlated with the final performance on the spatial task. In Experiment II, rats received intra-hippocampal injections of a specific CaM-kinase II inhibitor-KN-62-before each training session. In comparison with the vehicle-injected controls, pretraining injection of KN-62 retarded acquisition in the spatial task but had no effect on the nonspatial task. These results, taken together, indicated that the activation of CaM-kinase II in the hippocampus is not only correlated to the degree of spatial training on the Morris water maze, but may also underlie the neural mechanism subserving spatial memory.
Tan
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SE
Department of Psychology, Kaohsiung Medical College, Taiwan, R.O.C.
Liang
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KC
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D007858:Learning / Q000502:physiology*; D008124:Locomotion / Q000502:physiology; D008297:Male; D018782:Maze Learning / Q000502:physiology; D011494:Protein Kinases / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D002147:Calmodulin; D011494:Protein Kinases; D002118:Calcium