Potassium current suppression in patients with peripheral nerve hyperexcitability.

Capa:Potassium current suppression in patients with peripheral nerve hyperexcitability.

Autor(es): Nagado T.; Arimura K.; Sonoda Y.; Kurono A.; Horikiri Y.; Kameyama A.; Kameyama M.; Pongs O; Osame M


Resumo: Acquired neuromyotonia (Isaac's syndrome) is considered to be an autoimmune disease, and the pathomechanism of nerve hyperexcitability in this syndrome is correlated with anti-voltage-gated K(+) channel (VGKC) antibodies. The patch-clamp technique was used to investigate the effects of immunoglobulins from acquired neuromyotonia patients on VGKCs and voltage-gated Na(+) channels in a human neuroblastoma cell line (NB-1). K(+) currents were suppressed in cells that had been co-cultured with acquired neuromyotonia patients' immunoglobulin for 3 days but not for 1 day. The activation and inactivation kinetics of the outward K(+) currents were not altered by these immunoglobulins, nor did the immunoglobulins significantly affect the Na(+) currents. Myokymia or myokymic discharges, with peripheral nerve hyperexcitability, also occur in various neurological disorders such as Guillain-Barré syndrome and idiopathic generalized myokymia without pseudomyotonia. Immuno-globulins from patients with these diseases suppressed K(+) but not Na(+) currents. In addition, in hKv 1.1- and 1.6-transfected CHO (Chinese hamster ovary)-K1 cells, the expressed VGKCs were suppressed by sera from acquired neuromyotonia patients without a change in gating kinetics. Our findings indicate that nerve hyperexcitability is mainly associated with the suppression of voltage-gated K(+) currents with no change in gating kinetics, and that this suppression occurs not only in acquired neuromyotonia but also in Guillain-Barré syndrome and idiopathic generalized myokymia without pseudomyotonia.


Imprenta: Brain : a Journal of Neurology, v. 122, n. 11, p. 2057-2066, 1999


Identificador do objeto digital: 10.1093/brain/122.11.2057


Descritores: Guillain-Barre Syndrome - Biosynthesis


Data de publicação: 1999