title: Immunosuppressors inhibit voltage-gated potassium channels in human peripheral blood lymphocytes.
abstract: The effects of immunosuppressive agents on the potassium current of human peripheral blood lymphocytes have been studied using the whole-cell patch-clamp technique. Cyclosporin A (10 micrograms/ml), rapamycin (10 micrograms/ml) and FK-506 (2.5 micrograms/ml) reduced the peak K+ current by approximately 40, 30 and 40% of the control, respectively, without any change in the reversal potential of the current. The current inhibition was similar at all membrane potentials studied and was accompanied with an increase in the rate of K+ current inactivation. Membrane potential measurements in current-clamp showed a marked depolarization of the membrane (>10 mV) upon the addition of either immunosuppressor to the cells. Our findings revealed that the voltage-dependent potassium current in human peripheral blood lymphocytes is inhibited by Cyclosporin A and other immunosuppressors, resulting in a depolarized membrane potential.
authors.affiliation: Department of Biophysics, University Medical School of Debrecen, Hungary.
authors.forename: G
authors.initials: G
authors.lastname: Panyi
authors.forename: R
authors.initials: R
authors.lastname: Gaspar
authors.forename: Z
authors.initials: Z
authors.lastname: Krasznai
authors.forename: J J
authors.initials: JJ
authors.lastname: ter Horst
authors.forename: M
authors.initials: M
authors.lastname: Ameloot
authors.forename: A
authors.initials: A
authors.lastname: Aszalos
authors.forename: P
authors.initials: P
authors.lastname: Steels
authors.forename: S
authors.initials: S
authors.lastname: Damjanovich
mesh_terms: D016572:Cyclosporine / Q000494:pharmacology; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D015640:Ion Channel Gating; D008214:Lymphocytes / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D011090:Polyenes / Q000494:pharmacology; D026902:Potassium Channel Blockers; D020123:Sirolimus; D016559:Tacrolimus / Q000494:pharmacology
chemical_list: D007166:Immunosuppressive Agents; D011090:Polyenes; D026902:Potassium Channel Blockers; D016572:Cyclosporine; D020123:Sirolimus; D016559:Tacrolimus