Photoperiod-Dependent Homeostatic Plasticity In Tectal Neural Circuit

Neurons counteract over-excitation or inhibition by regulating synaptic intensity to maintain homeostatic plasticity through a negative feedback mechanism.Neurons can adapt to the changes of network activity and thus maintain normal functional activity.The regulation of homeostatic plasticity is dependent on the development stage,cell type and experimental conditions.Using Xenopus laevis tadpoles as model animals,we studied the changes of excitatory synaptic transmission induced by increasing or decreasing visual input through changing the duration of light exposure.The results showed that the amplitudes of mEPSC and the evoked responses were significantly decreased by increasing visual activity,while the intrinsic excitability was significantly increased.At the same time,we found that the expression of Rab5 c was significantly increased by increasing the duration of light exposure,while the mEPSC amplitudes returned to the normal level when knockdown the expression of Rab5 c by a morpholino against Rab5 c.The results showed that increasing visual activity may influence the trafficking of postsynaptic AMPA receptors by Rab5 c and regulate homeostatic plasticity of tectal neural circuit.