Barresi Massimo, Caldera Maria, Grasso Claudia, Li Volsi Guido, Licata Flora, Santangelo Francesca
Dipartimento di Scienze Fisiologiche (University of Catania), Catania, Italy.
Neurosci Lett. 2009 Oct 30;464(3):173-8. doi: 10.1016/j.neulet.2009.08.035. Epub 2009 Aug 20.
Increases in firing rate induced in secondary vestibular neurons by microiontophoretic application of glutamate were studied during long-lasting applications of noradrenaline (NA) and/or its antagonists and agonists. Sixty-nine percent of the tested neurons, scattered through all nuclei of the vestibular complex, modified their responsiveness to glutamate in the presence of NA. The effects were depressive in a majority (40%) and enhancing in a minority (29%) of cases. NA application depressed responses to glutamate more often than it increased them in lateral, medial and superior vestibular nuclei, while the reverse was true for the spinal nucleus. The mean intensities of NA-evoked effects were comparable in the various nuclei. The enhancing effects of NA were antagonized by application of the alpha2 receptor antagonist yohimbine, and their depressive effects were enhanced by the beta receptor antagonist timolol. It is concluded that NA exerts a control on the processing of vestibular information and that this modulation is exerted by at least two mechanisms involving alpha2 and beta noradrenergic receptors.
在去甲肾上腺素（NA）及其拮抗剂和激动剂的长期应用过程中，研究了通过微量离子电泳施加谷氨酸诱导的次级前庭神经元放电率的增加。69% 的受试神经元分散在前庭复合体的所有核中，在存在 NA 的情况下改变了它们对谷氨酸的反应性。在大多数（40%）情况下，效应是抑制性的，在少数（29%）情况下是增强性的。在前庭外侧核、内侧核和上核中，NA 的应用抑制对谷氨酸的反应比增强反应更常见，而在脊髓核中则相反。NA 诱发效应的平均强度在各个核中相当。NA 的增强效应可通过应用 α2 受体拮抗剂育亨宾来拮抗，其抑制效应可通过 β 受体拮抗剂噻吗洛尔增强。得出的结论是，NA 对前庭信息的处理施加控制，并且这种调节是通过至少两种涉及 α2 和 β 去甲肾上腺素能受体的机制来实现的。
