Two types of K(+) channel subunit, Erg1 and KCNQ2/3, contribute to the M-like current in a mammalian neuronal cell.
The potassium M current was originally identified in sympathetic ganglion cells, and analogous currents have been reported in some central neurons and also in some neural cell lines. It has recently been suggested that the M channel in sympathetic neurons comprises a heteromultimer of KCNQ2 and KCNQ3 (Wang et al., 1998) but it is unclear whether all other M-like currents are generated by these channels. Here we report that the M-like current previously described in NG108-15 mouse neuroblastoma x rat glioma cells has two components, "fast" and "slow", that may be differentiated kinetically and pharmacologically. We provide evidence from PCR analysis and expression studies to indicate that these two components are mediated by two distinct molecular species of K(+) channel: the fast component resembles that in sympathetic ganglia and is probably carried by KCNQ2/3 channels, whereas the slow component appears to be carried by merg1a channels. Thus, the channels generating M-like currents in different cells may be heterogeneous in molecular composition.
Selyanko
A A
AA
Department of Pharmacology, University College London, London, WC1E 6BT, United Kingdom.
Hadley
J K
JK
Wood
I C
IC
Abogadie
F C
FC
Delmas
P
P
Buckley
N J
NJ
London
B
B
Brown
D A
DA
D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D016466:CHO Cells; D002454:Cell Differentiation; D006224:Cricetinae; D005910:Glioma; D006801:Humans; D006822:Hybrid Cells; D007211:Indoles / Q000494:pharmacology; D051658:KCNQ2 Potassium Channel; D051659:KCNQ3 Potassium Channel; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009447:Neuroblastoma; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D015221:Potassium Channels / Q000502:physiology*; D024642:Potassium Channels, Voltage-Gated; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology; D013424:Sulfanilamides / Q000494:pharmacology; D017783:Superior Cervical Ganglion / Q000502:physiology*; D014162:Transfection; D000096926:Benzenesulfonamides
D001562:Benzimidazoles; D007211:Indoles; D051658:KCNQ2 Potassium Channel; D051659:KCNQ3 Potassium Channel; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D011725:Pyridines; D043643:Receptor, Muscarinic M1; D011976:Receptors, Muscarinic; D013424:Sulfanilamides; C496914:KCNQ2 protein, human; C496916:KCNQ3 protein, human; C496915:Kcnq2 protein, rat; C496917:Kcnq3 protein, mouse; C496918:Kcnq3 protein, rat; C073190:WAY 123398; D000096926:Benzenesulfonamides; C061017:linopirdine