Kv4.3-mediated A-type K+ currents underlie rhythmic activity in hippocampal interneurons.
Hippocampal-dependent learning and memory processes are associated with theta frequency rhythmic activity. Interneuron and pyramidal cell network interactions underlie this activity, but contributions of interneuron voltage-gated membrane conductances remain unclear. We show that interneurons at the CA1 lacunosum-moleculare (LM) and radiatum (RAD) junction (LM/RAD) display voltage-dependent subthreshold membrane potential oscillations (MPOs) generated by voltage-gated tetrodotoxin-sensitive Na+ and 4-aminopyridine (4-AP)-sensitive K+ currents. They also exhibit prominent 4-AP-sensitive A-type K+ currents, with gating properties showing activation at subthreshold membrane potentials. We found that LM/RAD cells are part of specific interneuron subpopulations expressing the K+ channel subunit Kv4.3 and their transfection with Kv4.3 small interfering RNA selectively impaired A-type K+ currents and MPOs. Thus, our findings reveal a novel function of Kv4.3-mediated A-type K+ currents in the generation of intrinsic MPOs in specific subpopulations of interneurons that may participate in hippocampal theta-related rhythmic activity.
Bourdeau
Mathieu L
ML
Département de Physiologie, Groupe de Recherche sur le Système Nerveux Central, Université de Montréal, Montréal, Québec, Canada H3C 3J7.
Morin
France
F
Laurent
Charles E
CE
Azzi
Mounia
M
Lacaille
Jean-Claude
JC
D000818:Animals; D002460:Cell Line; D004553:Electric Conductivity; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009991:Oscillometry; D010507:Periodicity; D015221:Potassium Channels / Q000502:physiology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D051672:Shal Potassium Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015222:Sodium Channels / Q000502:physiology
D015221:Potassium Channels; D034741:RNA, Small Interfering; D051672:Shal Potassium Channels; D015222:Sodium Channels