FEBS Letters | |
Down‐regulation of non‐L‐, non‐N‐type (Q‐like) Ca2+ channels by Lambert‐Eaton myasthenic syndrome (LEMS) antibodies in rat insulinoma RINm5F cells | |
Sher, E.1  Carbone, E.2  Magnelli, V.2  Parlatore, E.2  Grassi, C.3  | |
[1] CNR Center for Cytopharmacology, Milan, Italy;Department of Neuroscience, Corso Raffaello 30, Turin, Italy;Institute of Human Physiology, UCSC, Rome, Italy | |
关键词: Ca2+ channel; Lambert-Eaton myasthenic syndrome; IgG; Insulinoma; RINm5F cell; | |
DOI : 10.1016/0014-5793(96)00465-6 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
The action exerted on non-L-, non-N-type (Q-like) Ca2+ channels by immunoglobulins G (IgGs) obtained from two patients with Lambert-Eaton myasthenic syndrome (LEMS) was investigated in the rat insulinoma RINm5F cell line. LEMS IgGs reduced by 30–36% the whole-cell Ba2+ currents through Q-like Ca2+ channels at +10 mV without significantly modifying their voltage dependence and activation kinetics. Single- and multiple-channel recordings in cell-attached and outside-out patches of cells treated with LEMS IgGs showed no significant changes of the channel elementary properties but rather a decreased number of active channels per patch. This suggests that Q-like current depression by LEMS autoantibodies is mostly due to a down-regulation of functioning Ca 2+ channels. In agreement with previous observations, LEMS IgGs also reduced by 20–33% the dihydropyridine-sensitive (L-type) Bat+ current. The suggested down-regulation of Q-like channels by LEMS IgGs in RINm5F cells may have a functional correlation with the depressive action of LEMS autoantibodies on the PIQ-type Ca2+ channels controlling acetylcholine release from mammalian neuromuscular junctions.
【 授权许可】
Unknown
【 预 览 】
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