梯形体内侧核中的 GABAρ 表达。

GABAρ expression in the medial nucleus of the trapezoid body.

机构信息

Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, Juriquilla, Querétaro, Qro. CP 76230, Mexico.

出版信息

Neurosci Lett. 2013 Jan 4;532:23-8. doi: 10.1016/j.neulet.2012.10.024. Epub 2012 Nov 2.

DOI:10.1016/j.neulet.2012.10.024

PMID:23123780

Abstract

The Calyx of Held (CoH) synapse is the largest synapse in mammals. It is located in the medial nucleus of the trapezoid body (MNTB) and forms part of the auditory pathway. Modest GABAergic signaling is present in the CoH before hearing onset, when glutamatergic transmission predominates. In mice, after postnatal day 12, the absolute strength of glycinergic transmission increases markedly, while GABAergic signaling remains constant. The persistent GABAergic transmission in the MNTB is mediated by a slowly desensitizing component. In this study we recorded GABA-mediated responses from postsynaptic principal neurons (PPNs) of the MNTB and found that they are sensitive to TPMPA, suggesting the involvement of GABAρ subunits. RT-PCR and immunohistofluorescence in the MNTB confirmed GABAρ expression in PPNs. Interestingly, GABAρ3 was present only before hearing onset, and there was a switch to GABAρ1 and GABAρ2 expression in adult animals.

摘要

柯勒氏复合体（CoH）突触是哺乳动物中最大的突触。它位于梯形体内侧核（MNTB）中，是听觉通路的一部分。在听觉出现之前，CoH 中存在适度的 GABA 能信号传递，此时谷氨酸能传递占主导地位。在小鼠中，出生后第 12 天之后，甘氨酸能传递的绝对强度显著增加，而 GABA 能信号传递保持不变。MNTB 中持续的 GABA 能信号传递是由一个缓慢脱敏的成分介导的。在这项研究中，我们记录了 MNTB 中的突触后主神经元（PPNs）的 GABA 介导的反应，发现它们对 TPMPA 敏感，这表明 GABAρ 亚基的参与。MNTB 中的 RT-PCR 和免疫荧光证实了 PPNs 中 GABAρ 的表达。有趣的是，GABAρ3 仅在听觉出现之前存在，而在成年动物中存在从 GABAρ3 向 GABAρ1 和 GABAρ2 表达的转换。