Relationship of brain-derived neurotrophic factor and AMPA receptor without GLuR2 in enhancing the function of AMPA and activating synaptic vesicle

Abstract:

Objective：To study the relationship of brain-derived neurotrophic factor（BDNF） and α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor（AMPA） receptor without GLuR2，to further regulate BDNF and the receptor of AMPA and to pro－vide theoretical basis for protecting hippocampal neuron. Methods：Eight pregnant SD rats of 17-18 d were selected and their fetal rats’ hippocampal cells were separated and cultured. The cells were randomly divided into normal group（N group），BDNF group，N+NASPM group and BDNF+NASPM group. All groups were treated with Synapto GreenTM C4（FM1-43） and patch clamp. Quantity of synaptic vesicles and the function of synapse were recorded. Results：Results showed that the second fluorescene intensity of BDNF group（750.23±137.81） was obvious higher than that of N group（554.41±16.42）（ χ2=7.22，P=0.030）；while fluorescene intensity of BDNF+NASPM group（525.93±72.64） was lower than that of BDNF group（ χ2=13.18，P=0.000），indicating that BDNF regulating AMPA receptor without GluR2 may be one of the mechanisms of BDNF increasing the function of synaptic vesicle. What’s more，BDNF group had higher frequency（3.34±0.280） and amplitude（-25.00±2.57） of AMPA receptor micro excitatory postsynaptic currents compared with those of N group（1.730±0.217）（P=0.000） and （-16.3±1.98）（P=0.000）. After BDNF group being adding NASPM，frequency（1.740±0.207）（P=0.000） and amplitude（-15.50±2.52）（P=0.000） were reduced，indicating that BDNF can increase AMPA receptor mEPSCs by regulating the AMPA receptor without GluR2. Conclusions：BDNF may partially adjust the AMPA receptor without GluR2 subunit to enhance the function of AMPA and activate the synaptic vesicles.