The possible role of TASK channels in rank-ordered recruitment of motoneurons in the dorsolateral part of the trigeminal motor nucleus

Keiko Okamoto, Norihito Emura, Hajime Sato, Yuki Fukatsu, Mitsuru Saito, Chie Tanaka, Yukako Morita, Kayo Nishimura, Eriko Kuramoto, Dong Xu Yin, Kazuharu Furutani, Makoto Okazawa, Yoshihisa Kurachi, Takeshi Kaneko, Yoshinobu Maeda, Takashi Yamashiro, Kenji Takada, Hiroki Toyoda, Youngnam Kang

Research output: Contribution to journalArticle

3 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)497-506
Number of pages10
JournaleNeuro
Volume3
Issue number3
DOIs
StatePublished - Jan 1 2016
Externally publishedYes

ASJC Scopus subject areas

  • Medicine(all)

Fingerprint Dive into the research topics of 'The possible role of TASK channels in rank-ordered recruitment of motoneurons in the dorsolateral part of the trigeminal motor nucleus'. Together they form a unique fingerprint.

  • Cite this

    Okamoto, K., Emura, N., Sato, H., Fukatsu, Y., Saito, M., Tanaka, C., Morita, Y., Nishimura, K., Kuramoto, E., Yin, D. X., Furutani, K., Okazawa, M., Kurachi, Y., Kaneko, T., Maeda, Y., Yamashiro, T., Takada, K., Toyoda, H., & Kang, Y. (2016). The possible role of TASK channels in rank-ordered recruitment of motoneurons in the dorsolateral part of the trigeminal motor nucleus. eNeuro, 3(3), 497-506. https://doi.org/10.1523/ENEURO.0138-16.2016