Effects of myasthenia gravis patients' sera with different autoantibodies on slow K+ current at mouse motor nerve terminals.
The antibodies against pre-synaptic membrane receptor (PsmR) and acetylcholine receptor (AChR) in serum samples of myasthenia gravis (MG) patients and healthy donors were tested by enzyme-linked immunosorbent assays (ELISA). The serum samples of eight MG patients with different autoantibodies and those of six healthy donors without these two kinds of autoantibodies were collected to investigate their effects on the peri-neurially recorded membrane currents at mouse motor nerve terminals. After inhibition of both fast and Ca(2+)-dependent K+ currents by tetra-ethylammonium (TEA), a positive wave was revealed, which was a balance of the slow K+(Ik,s) and Ca2+ currents (ICa). Application of anti-PsmR antibody negative MG sera and healthy donor sera, whether anti-AChR antibody positive or negative, did not affect the positive wave. However, the positive wave shifted to prolonged Ca(2+)-plateau when adding two of four anti-PsmR antibody positive serum samples from MG patients, indicating an inhibition of Ik,s by anti-PsmR antibody positive sera. Meanwhile, all serum samples derived from either patients or healthy donors did not affect INa.
Xu
Tong-Hui
TH
Key Laboratory of Neurobiology, Institute of Physiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, P.R. China.
Ding
Jun
J
Shi
Yu-Liang
YL
Li
Mu-Feng
MF
Lu
Chuan-Zhen
CZ
Qiao
Jian
J
D000293:Adolescent; D000328:Adult; D000818:Animals; D001323:Autoantibodies / Q000276:immunology* / Q000494:pharmacology; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004594:Electrophysiology; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008875:Middle Aged; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D009157:Myasthenia Gravis / Q000097:blood* / Q000276:immunology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D017661:Receptors, Presynaptic / Q000187:drug effects / Q000502:physiology; D013570:Synaptic Membranes / Q000187:drug effects / Q000502:physiology
D001323:Autoantibodies; D015221:Potassium Channels; D017661:Receptors, Presynaptic