title: The Possible Role of TASK Channels in Rank-Ordered Recruitment of Motoneurons in the Dorsolateral Part of the Trigeminal Motor Nucleus.
abstract: Because a rank-ordered recruitment of motor units occurs during isometric contraction of jaw-closing muscles, jaw-closing motoneurons (MNs) may be recruited in a manner dependent on their soma sizes or input resistances (IRs). In the dorsolateral part of the trigeminal motor nucleus (dl-TMN) in rats, MNs abundantly express TWIK (two-pore domain weak inwardly rectifying K channel)-related acid-sensitive-K(+) channel (TASK)-1 and TASK3 channels, which determine the IR and resting membrane potential. Here we examined how TASK channels are involved in IR-dependent activation/recruitment of MNs in the rat dl-TMN by using multiple methods. The real-time PCR study revealed that single large MNs (>35 μm) expressed TASK1 and TASK3 mRNAs more abundantly compared with single small MNs (15-20 μm). The immunohistochemistry revealed that TASK1 and TASK3 channels were complementarily distributed in somata and dendrites of MNs, respectively. The density of TASK1 channels seemed to increase with a decrease in soma diameter while there were inverse relationships between the soma size of MNs and IR, resting membrane potential, or spike threshold. Dual whole-cell recordings obtained from smaller and larger MNs revealed that the recruitment of MNs depends on their IRs in response to repetitive stimulation of the presumed Ia afferents. 8-Bromoguanosine-cGMP decreased IRs in small MNs, while it hardly changed those in large MNs, and subsequently decreased the difference in spike-onset latency between the smaller and larger MNs, causing a synchronous activation of MNs. These results suggest that TASK channels play critical roles in rank-ordered recruitment of MNs in the dl-TMN.
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Okamoto
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
authors.forename: Norihito
authors.initials: N
authors.lastname: Emura
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry , Suita, Osaka 565-0871, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Sato
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Removable Prosthodontics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Fukatsu
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Oral Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
authors.forename: Mitsuru
authors.identifier: 0000-0002-5389-746X
authors.initials: M
authors.lastname: Saito
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Removable Prosthodontics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Tanaka
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
authors.forename: Yukako
authors.initials: Y
authors.lastname: Morita
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan; Department of Orthodontics and Dentofacial Orthopedics, Osaka University Graduate School of Dentistry, Suita, Osaka 565-0871, Japan.
authors.forename: Kayo
authors.initials: K
authors.lastname: Nishimura
authors.affiliation: Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; Department of Oral Anatomy and Cell Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
authors.forename: Eriko
authors.initials: E
authors.lastname: Kuramoto
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry , Suita, Osaka 565-0871, Japan.
authors.forename: Dong
authors.initials: D
authors.lastname: Xu Yin
authors.affiliation: Department of Pharmacology, Graduate School of Medicine, Osaka University , Suita, Osaka 565-0871, Japan.
authors.forename: Kazuharu
authors.identifier: 0000-0002-9680-2205
authors.initials: K
authors.lastname: Furutani
authors.affiliation: Department of Vascular Physiology, National Cardiovascular Center Research Institute , Suita, Osaka 565-8565, Japan.
authors.forename: Makoto
authors.identifier: 0000-0002-8564-0124
authors.initials: M
authors.lastname: Okazawa
authors.affiliation: Department of Pharmacology, Graduate School of Medicine, Osaka University , Suita, Osaka 565-0871, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kurachi
authors.affiliation: Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University , Kyoto 606-8501, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneko
authors.affiliation: Department of Removable Prosthodontics, Osaka University Graduate School of Dentistry , Suita, Osaka 565-0871, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics , Osaka University Graduate School of Dentistry , Suita, Osaka 565-0871, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamashiro
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics , Osaka University Graduate School of Dentistry , Suita, Osaka 565-0871, Japan.
authors.forename: Kenji
authors.identifier: 0000-0001-5760-4188
authors.initials: K
authors.lastname: Takada
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry , Suita, Osaka 565-0871, Japan.
authors.forename: Hiroki
authors.identifier: 0000-0002-9907-7176
authors.initials: H
authors.lastname: Toyoda
authors.affiliation: Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry , Suita, Osaka 565-0871, Japan.
authors.forename: Youngnam
authors.initials: Y
authors.lastname: Kang
mesh_terms: D000818:Animals; D048429:Cell Size; D006152:Cyclic GMP / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D009046:Motor Neurons / Q000166:cytology / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D009865:Oocytes; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D024683:Potassium Channels, Tandem Pore Domain / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017208:Rats, Wistar; D046509:Tissue Culture Techniques; D066266:Trigeminal Motor Nucleus / Q000166:cytology / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: C407082:Kcnk9 protein, rat; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D024683:Potassium Channels, Tandem Pore Domain; D012333:RNA, Messenger; C511784:TASK3 protein, mouse; C420132:potassium channel subfamily K member 3; D006152:Cyclic GMP
keywords: TASK channel; input resistance; leak potassium channel; recruitment; trigeminal motoneuron