Long-term Effects Of Developmental Seizures And Physical Exercise On Learning, Memory And CaMK Ⅱ Expression In Hippocampus

[Objectives] To explore the long-term effects of developmental seizures and physical exercise on learning, memory and the expression of calcium/calmodulin- dependent protein kinase II (CaMKII) in hippocampus.[Methods] The authors assigned twelve developmental rats for each group: the single-seizure group (SS), the recurrent-seizure group (RS) and the control group. The volatile agent flurothyl was used to induce 30 min seizure Attack.At postnatal day 6(P6), the single seizures induced only once and recurrent seizures induced once per day for consecutive 6 days. Control rats were placed into the container for an equal amount of time to their counterpart without exposure to flurothyl.At P27～P31,P58～P61,P80～P82, Morris water- maze test were performed three times to evaluate spatial memory capacity.During this time ,at P51～P56, the RS and SS groups were submitted to an aerobic exercise program 30min per day for consecutive 6 days .The control group was maintained in the treadmill for the same time as the training group without being submitted to physical exercise. At last, we detected the expresstion of CaMKⅡin brain.[Results] The escape latency of RS group was much longer than that of SS group and control group.There was no significant diference between SS group and control group.After physical exercise,the diference of escape latency in three groups is not significant in the last Morris water-maze tests.As far as Search strategy is concerned, the RS group was the worst. In the three memory tests,as for the distance ratioin between the origin platform quadrant to total distance,the RS group was the worst. The expresstion of CaMKⅡin Cortex,Dentate and Hilus,the RS group was the least.[Conclusions] Recurrent but not single prolonged seizures might cause long-term effects on learning and memory, which may be associated with the down-regulated expression of CaMKII mRNA in hippocampus. Physical exercise may improve the learning capacity of RS group but with no effect on memory capacity of RS group.