Excitatory sodium currents of NH15-CA2 neuroblastoma x glioma hybrid cells are differently affected by interleukin-2 and interleukin-1beta.
The neuroblastoma x glioma hybrid cell line NH15-CA2 was used to test the effects of two interleukins on neuronal Na+ channels. The cells were cultured in the presence of dibutyryl cAMP and retinoic acid, which yielded a high expression of Na+ channels so that the cells were excitable. Na+ currents were triggered and recorded in the whole-cell recording mode. Comparison of the effects of tetrodotoxin and mu-conotoxin established that the expressed Na+ channels were of the neuronal type. Bath-applied recombinant human interleukin-2 (rIL-2) had a reversible inhibitory effect on the Na+ currents, although to a lesser extent than on muscular Na+ currents (more than 1000 U/ml required for 50% block in NH15-CA2 cells vs 500 U/ml in myoballs). The current/voltage relationship was not affected by the presence of rIL-2, but the steady-state inactivation curve was shifted by -7.7 +/- 4.8 mV (mean +/- SD, n=18). Recombinant human interleukin-1beta (rIL-1beta), applied at 1000 U/ml, showed an inhibitory effect on the Na+ currents in about one-third of the cells tested. The mechanism of inhibition was different from that of rIL-2, as rIL-1beta seemed to cause a block without affecting voltage dependence or kinetics of the channels.
Hamm
S
S
Abteilung für Allgemeine Physiologie der Universität Ulm, D-89069 Ulm, Germany.
Rüdel
R
R
Brinkmeier
H
H
D000818:Animals; D004553:Electric Conductivity; D006706:Homeostasis; D006822:Hybrid Cells; D007375:Interleukin-1 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D051379:Mice; D009474:Neurons / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D011994:Recombinant Proteins; D015222:Sodium Channels / Q000187:drug effects* / Q000502:physiology*; D014407:Tumor Cells, Cultured
D007375:Interleukin-1; D007376:Interleukin-2; D011994:Recombinant Proteins; D015222:Sodium Channels