Tonic inhibition in spinal ventral horn interneurons mediated by α₅ subunit-containing GABA_A receptors

详细信息    查看全文

• 作者：Alberto Castro^a ; Justo Aguilar^a ; Ricardo Gonz&#xe1 ; lez-Ram&#xed ; rez^b ; Emanuel Loeza-Alcocer^a ; Martha Canto-Bustos^a ; Ricardo Felix^c ; Rodolfo Delgado-Lezama^a ; ^{rdelgado@fisio.cinvestav.mx" rel="nofollow}
• 关键词：GABA_A receptors ; Ion channels ; L-655708 ; Spinal cord ; Ventral horn interneurons
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2011
• 出版时间：19 August 2011
• 年：2011
• 卷：412
• 期：1
• 页码：26-31
• 全文大小：659 K
• ISSN：S0006291X11012459

文摘

GABA_A receptors mediate synaptic and tonic inhibition in many neurons of the central nervous system. These receptors can be constructed from a range of different subunits deriving from seven identified families. Among these subunits, α₅ has been shown to mediate GABAergic tonic inhibitory currents in neurons from supraspinal nuclei. Likewise, immunohistochemical and in situ hybridization studies have shown the presence of the α₅ subunit in spinal cord neurons, though almost nothing is known about its function. In the present report, using slices of the adult turtle spinal cord as a model system we have recorded a tonic inhibitory current in ventral horn interneurons (VHIs) and determined the functional contribution of the α₅ subunit-containing GABA_A receptors to this current. Patch clamp studies show that the GABAergic tonic inhibitory current in VHIs is not affected by the application of antagonists of the α_4/6 subunit-containing GABA_A receptors, but is sensitive to L-655708, an antagonist of the GABA_A receptors containing α₅ subunits. Last, by using RT-PCR and immunohistochemistry we confirmed the expression of the α₅ subunit in the turtle spinal cord. Together, these results suggest that GABA_A receptors containing the α₅ subunit mediate the tonic inhibitory currents observed in VHIs.