Effects of 17β-estradiol on synaptic plasticity in the rat medial vestibular nuclei

Abstract

Conclusion: This study shows that 17β-estradiol (E₂) can amplify the long-term potentiation (LTP) induced in the vestibular nuclei by high frequency stimulation (HFS), while potentiation induced by E₂ alone, which is unrelated to synaptic high frequency activation, is reversed by HFS. Objective: Like HFS, exogenous E₂ induces long-lasting enhancement of synaptic responses to vestibular afferent stimulation in the medial vestibular nuclei (MVN), through NMDA receptor activation. The aim of this study was to verify the possible interaction of E₂ and HFS in inducing LTP. Materials and methods: In rat brainstem slices, we analysed the modifications induced in the field potential evoked in the MVN by: 1) HFS delivered after induction of E₂ effect and 2) E₂ applied after induction of HFS-LTP. Results: HFS reversed the E₂-induced potentiation in most cases, while E₂ was able to increase the magnitude of potentiation induced by HFS.

• Long-term potentiation
• NMDA receptors
• high frequency stimulation
• de-potentiation
• vestibular field potential