title: Opposite long-term synaptic effects of 17β-estradiol and 5α-dihydrotestosterone and localization of their receptors in the medial vestibular nucleus of rats.
abstract: In brainstem slices of male rats, we examined in single neurons of the medial vestibular nucleus (MVN) the effect of exogenous administration of estrogenic (17β-estradiol, E2) and androgenic (5α-dihydrotestosterone, DHT) steroids on the synaptic response to vestibular afferent stimulation. By whole cell patch clamp recordings we showed that E2 induced synaptic long-term potentiation (LTP) that was cancelled by the subsequent administration of DHT. Conversely, DHT induced synaptic long-term depression (LTD) that was partially reversed by E2. The electrophysiological findings were supported by immunohistochemical analysis showing the presence of estrogen (ER: α and β) and androgen receptors (AR) in the MVN neurons. We found that a large number of neurons were immunoreactive for ERα, ERβ, and AR and most of them co-localized ERβ and AR. We also showed the presence of P450-aromatase (ARO) in the MVN neurons, clearly proving that E2 can be locally synthesized in the MVN. On the whole, these results demonstrate a role of estrogenic and androgenic signals in modulating vestibular synaptic plasticity and suggest that the enhancement or depression of vestibular synaptic response may depend on the local conversion of T into E2 or DHT.
authors.affiliation: Dipartimento di Medicina Interna, Sezione di Fisiologia Umana, Università di Perugia, Via del Giochetto, I-06126 Perugia, Italy. sgrassi@unipg.it
authors.forename: Silvarosa
authors.initials: S
authors.lastname: Grassi
authors.forename: Mariangela
authors.initials: M
authors.lastname: Scarduzio
authors.forename: Roberto
authors.initials: R
authors.lastname: Panichi
authors.forename: Cecilia
authors.initials: C
authors.lastname: Dall'Aglio
authors.forename: Cristiano
authors.initials: C
authors.lastname: Boiti
authors.forename: Vito E
authors.initials: VE
authors.lastname: Pettorossi
mesh_terms: D000818:Animals; D013196:Dihydrotestosterone / Q000494:pharmacology*; D004958:Estradiol / Q000494:pharmacology* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D011944:Receptors, Androgen / Q000378:metabolism*; D011959:Receptors, Estradiol / Q000378:metabolism*; D014726:Vestibular Nuclei / Q000378:metabolism / Q000502:physiology*
chemical_list: D011944:Receptors, Androgen; D011959:Receptors, Estradiol; D013196:Dihydrotestosterone; D004958:Estradiol
keywords: 17β-estradiol; 17β-oestradiol; 5α-Dihydrotestosterone; 5α-dihydrotestosterone; ACSF; ADP; AHP; ANOVA; AR; ARO; Androgen receptors; C; D; DAB; DHT; E2; EPSP; ER; Estradiol receptors; HFS; IR; Immunohistochemistry; LTD; LTP; MVN; P450-aromatase; PBS; T; V; Vestibular neurons; Vm; afterdepolarization potential; afterhyperpolarization; analysis of variance; androgen receptors; artificial cerebrospinal fluid; central; diaminobenzidine; dorsal; estrogen receptors; excitatory postsynaptic potential; high frequency stimulation; immunoreactive; long-term depression; long-term potentiation; medial vestibular nucleus; membrane potential; phosphate buffer solution; testosterone; ventral