Receptor‐mediated modulation of recombinant neuronal class E calcium channels

FEBS Letters

Hescheler, J¹  Grabsch, H¹  Mehrke, G¹  Pereverzev, A¹  Schneider, T¹ 

[1] Institute of Neurophysiology, University of Köln, Robert-Koch-Straße 39, D-50931 Köln, Germany

关键词: Cloned Ca2+ channel;    α 1E-Subunit;    HEK293 cell;    G-protein;    Ionic current;    Modulation;    Somatostatin;    Adenosine;    ATP;    Carbachol;    Electrophysiology;   

DOI  :  10.1016/S0014-5793(97)00437-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The modulation of a cloned neuronal calcium channel was studied in a human embryonic kidney cell line (HEK293). The HEK293 cells were stably transfected with the α _1Ed cDNA, containing the pore forming subunit of a neuronal class E calcium channel. Inward currents of 25±1.9 pA/pF (n=79) were measured with the cloned α _1Ed-subunit. The application of the peptide hormone somatostatin, carbachol, ATP or adenosine reduced the amplitude of Ca²⁺ and Ba²⁺ inward currents and exhibited a slowing of inactivation. This inhibitory effect by somatostatin was significantly impaired after pre-incubating the transfected cell line with pertussis toxin (PTX). Internal perfusion of the cells with the G-protein-inactivating agent GDP-β-S or with the permanently activating agent GTP-γ-S also attenuated the somatostatin effect. The inhibition indicates that modulation of the α _1Ed-mediated Ca²⁺ current involves pertussis toxin-sensitive G-proteins. The block of Ca²⁺ and Ba²⁺ inward currents by somatostatin is also found in cells expressing a truncated α _1Ed-subunit which lacks a 129-bp fragment in the C-terminus. This fragment corresponds to the major structural difference between two native human α _1E splice variants. As somatostatin inhibits inward currents through both, the cloned α _1Ed- and the truncated α _1Ed-DEL-subunit, the hormone-mediated modulation is independent from the presence of the 129-bp insertion in the C-terminus.

【 授权许可】

Unknown