title: Stimulatory actions of a novel thiourea derivative on large-conductance, calcium-activated potassium channels.
abstract: In this study, we examine whether an anti-inflammatory thiourea derivative, compound #326, actions on ion channels. The effects of compound #326 on Ca2+-activated K+channels were evaluated by patch-clamp recordings obtained in cell-attached, inside-out or whole-cell configuration. In pituitary GH3cells, compound #326 increased the amplitude of Ca2+-activated K+currents (IK(Ca)) with an EC50value of 11.6 μM, which was reversed by verruculogen, but not tolbutamide or TRAM-34. Under inside-out configuration, a bath application of compound #326 raised the probability of large-conductance Ca2+-activated K+(BKCa) channels. The activation curve of BKCachannels was shifted to less depolarised potential with no modification of the gating charge of the curve; consequently, the difference of free energy was reduced in the presence of this compound. Compound #326-stimulated activity of BKCachannels is explained by a shortening of mean closed time, despite its inability to alter single-channel conductance. Neither delayed-rectifier nor erg-mediated K+currents was modified. Compound #326 decreased the peak amplitude of voltage-gated Na+current with no clear change in the overall current-voltage relationship of this current. In HEK293T cells expressing α-hSlo, compound #326 enhanced BKCachannels effectively. Intriguingly, the inhibitory actions of compound #326 on interleukin 1β in lipopolysaccharide-activated microglia were significantly reversed by verruculogen, whereas BKCachannel inhibitors suppressed the expressions of inducible nitric oxide synthase. The BKCachannels could be an important target for compound #326 if similar in vivo results occur, and the multi-functionality of BKCachannels in modulating microglial immunity merit further investigation.
authors.affiliation: Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan.
authors.forename: Sheng-Nan
authors.initials: SN
authors.lastname: Wu
authors.affiliation: Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Jyh-Haur
authors.initials: JH
authors.lastname: Chern
authors.affiliation: Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Santai
authors.initials: S
authors.lastname: Shen
authors.affiliation: Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Hwei-Hisen
authors.initials: HH
authors.lastname: Chen
authors.affiliation: Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Ying-Ting
authors.initials: YT
authors.lastname: Hsu
authors.affiliation: Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Chih-Chin
authors.initials: CC
authors.lastname: Lee
authors.affiliation: Institute of Neuroscience, National Chengchi University, Taipei City, Taiwan.
authors.forename: Ming-Huan
authors.initials: MH
authors.lastname: Chan
authors.affiliation: Department of Pediatrics, Chi Mei Medical Center, Tainan City, Taiwan.
authors.forename: Ming-Chi
authors.initials: MC
authors.lastname: Lai
authors.affiliation: Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: Feng-Shiun
authors.identifier: http://orcid.org/0000-0002-5774-6538
authors.initials: FS
authors.lastname: Shie
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D020013:Calcium Signaling / Q000187:drug effects*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D015640:Ion Channel Gating / Q000187:drug effects; D007700:Kinetics; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits / Q000819:agonists* / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008564:Membrane Potentials; D008807:Mice, Inbred BALB C; D017628:Microglia / Q000187:drug effects / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000378:metabolism; D051381:Rats; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology*; D014162:Transfection
chemical_list: D000893:Anti-Inflammatory Agents; D002120:Calcium Channel Agonists; C587672:IL1B protein, mouse; D053583:Interleukin-1beta; C494841:KCNMA1 protein, human; C494842:Kcnma1 protein, rat; D051037:Large-Conductance Calcium-Activated Potassium Channel alpha Subunits; D008070:Lipopolysaccharides; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D013890:Thiourea; D002118:Calcium
keywords: Ca2+-activated K+ current; Na+ current; inflammation; large-conductance Ca2+-activated K+ channel; thiourea derivative