Analysis Of Long-Term Depression Induce By Glurs Agonist DHPG In The Hippocampal CA1 Ppathway Of Rats

OBJECTIVE: To investigate the effects of group I GluRs Agonist DHPG on long-term depression(LTD) in hippocampal CA1 pyramidal neurons of rats.METHODS: Wistar rats were anaesthetized with isoflurance prior to decapitation. The brain was removed and placed in an ice-cold solution for 5 minutes,and hippocampal slices(400μm)were prepared in the same solution. A cut was made between the CA3 and CA1 area in each slice to prevent epileptic activity. We also cut down DG for every slices. Then they were subsequently stored in artificial cerebrospinal fluid(ACSF). The slices were divided into 3 groups.DHPG(100μmol/l-200μmol/l) group and 8 slices in this group,DHPG and APV (50μmol/l) group,for 9 slices,PPR group, for 8 slices. Recordings were begun after 1 to 8 hours and were carried out in a submerged recording chamber, perfused with ACSF at a rate of 1.5-2ml/min and at room temperature(25oC). Picrotoxin(50μM) was present in the perfusion solution unless otherwise specified. We had recorded the data before given DHPG and after usded it by Electricphysiological Technology.RESULT : We got the baseline the data is 1.0049±0.101, added DHPG(100μmol/l-200μmol/l), the data is 0.7904±0.02197(n=8,t=15,p<0.01);When added AP5(NMDAR antagonist )to ASF, the baseline is 1.0224±0.0724, added DHPG (100μmol/l-200μmol/l) the data changed0.828±0.01475 (n=9, t=15,p<0.01);PPR before added DHPG (100μmol/l-200μmol/l) is 0.9525±0.1691,and after added drug is 1.0511±0.2934 .CONCLUSION: In our conductions, LTD is depended on I mGluRs, not NMDARs; and it is induced by postsynaptic mechanisms.