Effect of astrocyte-derived estrogen on the regulation of the synaptic transmission in rats / 第三军医大学学报

ABSTRACT

Objective To study the effect and the mechanism of astrocytes-derived estrogen on synaptic transmission. Methods Based on the model of pure cultures of neonatal cortical neurons, the experimental groups were designed as follows pure neuron culture (group P), ACM culture (group A), mixed culture of AST and neuron (group M), E_ 2 culture (group E), ACM+tamoxifen (estrogen receptor antagonist) culture (group A+T ), tamoxifen culture (group T). The difference among these groups of synaptic transmission was recorded by patch clamp and presynaptic vesicle releasing kinetics was marked by a dye named FM4-64. Results The mean amplitude and frequency of miniature postsynaptic currents (mPSCs) of group P, A, M, E, A+T and T were (20.5?2) pA, (13?4) min -1 ; (29.1?3) pA, (73?16) min -1 ; (31.3?3) pA, (78?20) min -1 ; (30.2?3) pA, (76?18) min -1 ; (24.5?2) pA, (35?10) min -1 ; (22.1?2) pA, (37?10) min -1 respectivily. The treatment of pure neuron culture with ACM increased synaptic transmission of pure cultured cortical neuron. Exogenic estradiol added into pure neurons can stimulate the effect of the ACM. Tamoxifen which was the antagonist of estrogen receptor could decrease most effect of ACM on synaptic transmission. The assaying of vesicle release marked by FM4-64 showed astrocytes-derived estrogenic enhancing synaptic transmission was at least mediated by strengthening presynaptic vesicle releasing. Conclusion The estrogen from astrocytes of neonatal rat cortex may enhance neuronal synaptic transmission mainly through estrogen receptor.