Effects And Possible Mechanism Study Of Abscisic Acid (ABA)on Learning And Memory Ability In Rats

Abscisic acid(ABA)is a key plant hormone presented in a wide range of animals(including humans)and has a variety of biological activities.As a direct derivative of carotenoids,ABA and retinoic acid(RA)have similar molecular structures,and RA has been reported to improve the spatial memory of rodents.It has been reported in the literature that ABA long-term administration can replace RA to improve special learning and memory,but its specific molecular mechanism is not clear.Objective: To investigate the effect of ABA administration on the spatial memory of adult SD rats;to investigate the effect of ABA on spine morphology;to examine the expression levels of NMDA receptor,Arc and NDR1/2 kinase to investigate the molecular mechanism.Methods: Sprague-Dawley(SD)rats were injected intraperitoneally with ABA(5 mg / kg / day,25 mg / kg / day,50 mg / kg / day)from postnatal week 1 to week 8.Dendritic spine morphology was examined using Golgi-Cox staining method and determined with Image J software.Western blotting method was employed to test the NMDA receptor,Arc and NDR1/2 proteins.Results: The behavioral test showed that the middle dose of ABA increased the duration spent in the target quadrant and the frequency of entry in the Morris water maze(MWM)detection test and reduced the latency for the target quadrant.In addition,we found that ABA resulted in significant changes in the structure of dendritic spines,as shown by increasing the complexity of dendritic spines,dendritic spine density and the proportion of mushroom-shaped dendritic spines in the hippocampus.We found that ABA does not affect the NMDA receptors R1,R2 and Arc protein expression,further investigation revealed that the expression that the expression of NDR1/2 protein was increased along with the essential downstream genes,withABA's administration.NDR1/2 shRNA was transfected into hippocampal neurons.We found that the expression of Rabin3 in NDR downstream gene was significantly decreased.It indicated that the NDR1/2 kinase pathway was involved in the regulation of ABA on maturation process of dendritic spine in hippocampal neurons.Conclusion: In conclusion,this study investigated and elucidated the effect of ABA on learning and memory in SD rats and the possible mechanism.