Effects Of Metformin On Neuronal Function Of Primary Visual Cortex In Elderly Animals

Aging causes a serious decline of the visual cortex inhibition system,thus destroy the excitation-inhibition balance,leading to an increase in neuron peak level,a decrease in signal-to-noise ratio,and a decrease in information processing capability.Studies have shown that metformin can induce the aggregation of inhibitory receptors in the postsynaptic membrane and enhance the inhibitory ability of the nervous system.There fore,we speculate that metformin may have great significance for improving the nervous system Excitation-inhibition balance abnormalities caused by aging and slowing down the nerve injury caused by aging.The primary visual cortex(?)is in the primary stage of visual information proces,its very important for the formation of visual perception and also one of the areas severely affected by aging.We plan to taking V1 region of elderly animals as a model,to study the effect of metformin on cortical excitation-inhibition system and explore its potential to improve visual function of aged animals.First,we took old cats as an experimental object to explore whether metformin can improve the response characteristics of primary visual cortex neurons under the influence of aging.We studied the effects of metformin on direction and orientation tuning,contrast sensitivity of neurons in primary visual cortex by analyzing the responses of neurons under different conditions through in vivo multichannel electrophysiological records.The results showed that under the action of metformin,the direction and orientation tuning ability and contrast sensitivity of neurons in the primary visual cortex of elderly animals were significantly improved.The imbalance of excitation-inhibition caused by aging is an important reason for visual function damage.Therefore,we speculate that metformin may enhance the cortical inhibition system,adjust the excitement-inhibition balance,reduce the damage caused by aging and improve the visual function of elderly animals.In order to explore the neural mechanism of metformin's regulation of the Excitation-inhibition balance of the nervous system.Taking mice as models,we detected the changes of excitatory and inhibitory transmitter receptors and their related proteins by western blot.The results show that metformin reduces the synthesis of excitatory transmitter(Glu)receptors and enhances the synthesis of inhibitory transmitter(GABA)receptors and related proteins.In addition,We also recorded and analyzed the effects of metformin on neuronal peak and directional tuning in primary visual cortex of mice through electrophysiological techniques.The results showed that the neuronal peak was significantly reduced and the direction and orientation bias was significantly improved.These results show that metformin can reduce the cortical excitation system and enhance the inhibition system by regulating the synthesis of related proteins and regulate the excitation-inhibition balance of the nervous system,thus enhancing visual function.By analyzing the experimental results we believe that metformin may reduce the excitatory system and improve the inhibitory system of the primary visual cortex by affecting the synthesis of related proteins,thereby having a certain ability to regulate the imbalance of excitation-inhibition in the nervous system caused by aging.The effect of metformin on visual cortex may have reference significance in neuroprotection.