[Effects of lanthanum on the phosphorylation of cAMP response element binding protein and expression of immediate early genes in the hippocampal CA3 area of rats].

Unlabelled: AOBJECTIVE: To study the effects of lanthanum (La) on calmodulin (CaM) activity, phosphorylation of CaM dependent protein kinase IV (CaMK IV), cAMP response element binding protein (CREB) and expression of c-fos, c-jun and egrl in the hippocampal CA3 area of rats.

Methods: Forty Wistar rats in pregnancy were divided randomly into four groups: control, 0.25%, 0.5% and 1.0% LaCl3-administrated groups. After birth,pups of LaC13-administrated groups were administrated with La by lactation before weaning, and then given with La by drinking water for one month. CaM activity was determined by phosphodiesterase. The protein expression levels of p-CaMK IV and p-CREB were measured by Western blotting,and c-fos,c-jun and egrl mRNA expression levels were detected by RT-PCR.

Results: CaM activity and protein expression levels of p-CaMK IV and p-CREB in the hippocampal CA3 area of three LaC13-administrated groups were lower significantly than those of control group, and presented dose-effect relationship to a certain extent. The expression levels of c-fos and c-jun mRNA in the hippocampal CA3 area of low and middle LaCl3-administrated groups were lower significantly than those of control group,and the expression levels of egrl mRNA in the hippocampal CA3 area of middle LaCl3-administrated group were lower significantly than those of control and low LaC13-administrated groups. The expression levels of c-fos, c-jun and egrl mRNA in the hippocampal CA3 area of high LaCl3-administrated group were lower significantly than those of control, low and middle LaCl3-administrated groups.

Conclusion: La could decrease CaM activity, CaMK IV and CREB phosphorylation, c-fos, c-jun and egrl mRNA expression in the hippocampal CA3 area and therefore cause learning and memory impairment of rats.