title: Knockout of Slo2.2 enhances itch, abolishes KNa current, and increases action potential firing frequency in DRG neurons.
abstract: Two mammalian genes, Kcnt1 and Kcnt2, encode pore-forming subunits of Na(+)-dependent K(+) (KNa) channels. Progress in understanding KNa channels has been hampered by the absence of specific tools and methods for rigorous KNa identification in native cells. Here, we report the genetic disruption of both Kcnt1 and Kcnt2, confirm the loss of Slo2.2 and Slo2.1 protein, respectively, in KO animals, and define tissues enriched in Slo2 expression. Noting the prevalence of Slo2.2 in dorsal root ganglion, we find that KO of Slo2.2, but not Slo2.1, results in enhanced itch and pain responses. In dissociated small diameter DRG neurons, KO of Slo2.2, but not Slo2.1, abolishes KNa current. Utilizing isolectin B4+ neurons, the absence of KNa current results in an increase in action potential (AP) firing and a decrease in AP threshold. Activation of KNa acts as a brake to initiation of the first depolarization-elicited AP with no discernible effect on afterhyperpolarizations.
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Pedro L
authors.initials: PL
authors.lastname: Martinez-Espinosa
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wu
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Chengtao
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Vivian
authors.initials: V
authors.lastname: Gonzalez-Perez
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Huifang
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Hongwu
authors.initials: H
authors.lastname: Liang
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Xia
authors.affiliation: Department of Anesthesiology, Washington University School of Medicine, St. Louis, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lingle
mesh_terms: D000200:Action Potentials; D000818:Animals; D005727:Ganglia, Spinal / Q000502:physiology*; D055786:Gene Knockout Techniques; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000172:deficiency* / Q000378:metabolism; D009474:Neurons / Q000502:physiology*; D010146:Pain; D015221:Potassium Channels / Q000172:deficiency* / Q000378:metabolism; D000081033:Potassium Channels, Sodium-Activated; D011537:Pruritus
chemical_list: C518649:Kcnt2 protein, mouse; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D000081033:Potassium Channels, Sodium-Activated; C479624:Slo2 protein, mouse
keywords: DRG; KNa current; SLO2; biophysics; itch; mouse; neuroscience; pain; structural biology