The Mechanism Of Some Subtypes Of Endocannabinoid/Endovanilloid Receptors Involved In Polyunsaturated Fatty Acids To Improve The Ability Of Spatial Learning And Memory In Rats

ObjectiveTo observe the effects of the optimal dosage of DHA, walnut oil, perilla seed oil, safflower oil,α-linoleic acid on the rats’ spatial learning and memory, and preliminarily explore the mechanism of therats’ spatial learning and memory enhanced by some CB and RPV subtype receptors involved inpolyunsaturated fatty acidsMethods56male SD rats (early weaning) were randomly divided into seven groups, respectively given theoptimal dosage of DHA(300mg/kg), walnut oil(2.445ml/kg), perilla seed oil(2.445ml/kg), safflower oil(1.650375g/kg), α-linoleic acid(1.3203g/kg)with the method of gavage for each group every day. Besides,two extra negative control groups were set and respectively given the CMC (0.49ml/100g)daily. One groupwhich removed fatty acids was lack of polyunsaturated fatty acids, and other ones were fed normal fodder.After8weeks of gavage, Ethnology test was done by Morris water maze, and determined the relativeamount of polyunsaturated fatty acids in the cell membranes of rats’ brain by GC, and then extract DNA ofhippocampus of rats to test the expression of genes CB1, CB2, TRPV1, TRPV2, TRPV3and TRPV4withthe method of Real-time PCR.Results(1)Morris water maze test: compared with negative control group, the escaping latency of DHA,walnut oil, perilla seed oil, safflower oil, and α-linoleic acid group was significantly shortened(P<0.01andP<0.05), and compared with EFA lack group, it also led to the same rule, while there were no obviousdifferences between EFA lack group and negative control group; compared with negative control group,DHA, walnut oil, perilla seed oil, and safflower oil group spent longer valid time in the targetquadrant(P<0.01and P<0.05), but α-linoleic acid group had no significant difference, and compared withEFA lack group, DHA, walnut oil, perilla seed oil, safflower oil, and α-linoleic acid group prolongedobviously(P<0.01and P<0.05), while there were no obvious differences between EFA lack group andnegative control group; compared with negative control group, the times of crossing platform of DHA,walnut oil, perilla seed oil, safflower oil, and α-linoleic acid group was increased clearly(P<0.01andP<0.05), and compared with EFA lack group, it also led to the same rule, while there were no obviousdifferences between EFA lack group and negative control group.(2)In the total cell membrane of the brain, the order of total content of n-3race PUF As was walnutgroup, perilla seed oil group, safflower oil group, DHA group, EFA lack group, negative control group,and α-linoleic acid group; the order of total content of n-6race PUFAs: α-linoleic acid group, negativecontrol group, DHA group, EFA lack group, walnut group, perilla seed oil group, and safflower oil group.The content of n-3race PUF As of each sample except α-linoleic acid group all increased, and n-6racePUFAs decreased, compared with negative control group. The difference between α-linoleic acid groupand negative control group was not very apparent.(3)Real-time PCR: compared with negative control group, the mRNA expression quantity ofCB1,TRPV1of DHA group, walnut group, perilla seed oil group, safflower oil group, and α-linoleic acidgroup significantly increased(P<0.01and P<0.05), while CB1of EFA lack group reduced verysignificantly(P<0.01), and TRPV1of EFA lack group was not obviously different; compared with negativecontrol group, the mRNA expression quantity of TRPV2of DHA group, walnut group, perilla seed oil group, safflower oil group, and α-linoleic acid group significantly reduced, but EFA lack group was notobviously different; the mRNA expression quantity of CB2, TRPV3and TRPV4had no significantdifference between groups.Conclusion(1)DHA, walnut oil, perilla seed oil, safflower oil, α-linoleic acid can all improve the rats’ spatiallearning and memory, but the degree of improvement is different.(2)The model rats spatial learning and memory enhanced, the content of n-3race PUFAs of total cellmembrane increased, meanwhile the content of n-3race PUFAs decreased.(3)The subtype receptors of CB1, CB2, TRPV1, TRPV2, TRPV3, and TRPV4did not take part in theimprovement of spatial learning and memory entirely, but selectively; PUF As on the improvement ofspatial learning and memory of rats may promote the expression of CB1and TRPV1of hippocampus ofrats and enhance the spatial learning and memory of rats by activating CB1and TRPV1of hippocampus ofrats.