RT Journal Article SR Electronic T1 Long-Term Potentiation in the Rat Medial Vestibular Nuclei Depends on Locally Synthesized 17β-Estradiol JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 10779 OP 10783 DO 10.1523/JNEUROSCI.1697-09.2009 VO 29 IS 34 A1 Grassi, Silvarosa A1 Frondaroli, Adele A1 Dieni, Cristina A1 Scarduzio, Mariangela A1 Pettorossi, Vito E. YR 2009 UL http://www.jneurosci.org/content/29/34/10779.abstract AB In male rat brainstem slices, we investigated the involvement of locally synthesized 17β-estradiol (E2) in the induction in the medial vestibular nucleus (MVN) of long-term potentiation (LTP) by high-frequency stimulation (HFS) of the primary vestibular afferents. We demonstrated that the blockade of aromatase by letrozole or of E2 receptors (ERα and ERβ) by ICI 182,780 prevented the HFS-induced LTP of the N1 wave of the evoked field potential (FP) without affecting baseline responses. Only prolonged afferent activation could induce low LTP. In contrast, HFS applied under a combined blockade of GABAA receptors and aromatase or ERs was still able to induce LTP, but it was significantly lower and slower. These findings demonstrate that E2 does not have a tonic influence on the activity of the MVN neurons and provide the first evidence of the crucial role played by local synthesis of E2 in inducing LTP. We suggest that the synthesis of E2 occurs after aromatase activation during HFS and facilitates the development of vestibular synaptic plasticity by influencing glutamate and GABA transmission.