The modulation of Group I metabotropic glutamate receptor on synaptic transmission efficiency in the Primary Visual Cortex of Monocular Deprivation Amblyopia Rat

Abstract Background :The occurrence of amblyopia is closely related to the glutamate receptors in visual cortex. The expression of metabotropic glutamate receptor 1 (mGluR1) in the visual cortex of rats with amblyopia has been proved to decrease, however, the role of mGluR1 in the synaptic transmission of visual cortex is not clear. This study aimed to investigate the effect of group I mGluR on the synaptic transmission efficiency in the primary visual cortex of monocular deprivation amblyopia rat. Methods The 14-day-old rads were rangomly divided intonormal control group and form-deprivation group,with 8 rats in each group. The eyelids of the left eye were sutured to establish the monocular form- deprivation amblyopia rat model,The rats visual cortex slices were prepared and incubated in artificial cerebrospinal fluid . Four groups of drugs that it is 3,5-dihydroxyphenylglycine( DHPG), LY367385, 2-methyl-6( phenyl acetylene) pyridine hydrochloride( MPEP) and DHPG, LY367385and MPEP and DHPG were added to every group, respectively.The extracellular recording technique was used to record the field excitatory postsynaptic potential (fEPSP) in the visual cortex. Results: After application of DHPG, the fEPSP-slope of the visual cortex was significantly increased in both normal rats and monocular deprivation amblyopia rats (P<0.001), but the increase of normal group was significantly higher than that of amblyopia group (P<0.05). Application of LY367385, a selective mGluR1 blocker or Application of MPEP, an mGluR5 blocker can partially reduce the DHPG-induced fEPSP-slope in both normal group and amblyopia group. Conclusions: These results demonstrate that the effect of modulation of group I mGluR (mGluR1, 5) on the synaptic transmission was reduced in the visual cortex of monocular deprivation amblyopia rat. found that agonist DHPG of Group I mGluRs increased synaptic transmission efficiency of neurons in visual cortex of normal rats and monocular form deprivation rats.