(-)-Baclofen-induced and constitutively active inwardly rectifying potassium conductances in cultured rat midbrain neurons

• Verfasst von: O'Callaghan, John F. X. [VerfasserIn]
• Verfasst von: Jarolimek, Wolfgang [VerfasserIn]
• Verfasst von: Lewen, Andrea [VerfasserIn]
• Verfasst von: Misgeld, Ulrich [VerfasserIn]
• Titel: (-)-Baclofen-induced and constitutively active inwardly rectifying potassium conductances in cultured rat midbrain neurons
• Verf.angabe: J.F.X. O’Callaghan, W. Jarolimek, A. Lewen, U. Misgeld
• E-Jahr: 1996
• Jahr: November 1996
• Umfang: 9 S.
• Teil: volume:433
• Teil: year:1996
• Teil: number:1
• Teil: pages:49-57
• Teil: extent:9
• Fussnoten: Gesehen am 26.04.2021
• Titel Quelle: Enthalten in: Pflügers Archiv
• Ort Quelle: Berlin : Springer, 1868
• Jahr Quelle: 1996
• Band/Heft Quelle: 433(1996), 1, Seite 49-57
• ISSN Quelle: 1432-2013
• DOI: doi:10.1007/s004240050247
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1755926405

Abstract

Biophysical and pharmacological properties, and development of the (-)-baclofen-induced potassium (KBac) conductance and the constitutively active inwardly rectifying potassium (KIR) conductance were characterised using the patch-clamp technique in cultured embryonic rat midbrain neurons. KBac conductance was induced by (-)-baclofen acting on γ-aminobutyric acid B (GABAB) receptors, and displayed a high degree of selectivity for potassium ions, an approximate square-root dependence of conductance on extracellular potassium concentration and strongly voltage-dependent activation. Ba2+ blocked the conductance in a voltage-independent manner, whereas Cs+ produced a voltage-dependent block. In the same preparation, the KIR conductance displayed biophysical properties indistinguishable from those of the KBac conductance. Block of KIR currents by Ba2+ was voltage independent (KI, 4 μM), whereas Cs+ produced a voltage-dependent block (KI, 370 μM at -100 mV, equivalent valence, z′, 1.67). The KBac and KIR conductances additionally displayed a strikingly similar pattern of development in culture; the specific conductance (nS/pF) of both conductances increased two- to three-fold between the first and second week in vitro, and remained constant thereafter.