title: Desmin and nerve terminal expression during embryonic development of the lateral pterygoid muscle in mice.
abstract: OBJECTIVE
  In adults, the lateral pterygoid muscle (LPM) is usually divided into the upper and lower head, between which the buccal nerve passes. Recent investigations have demonstrated foetal developmental changes in the topographical relationship between the human LPM and buccal nerve. However, as few studies have investigated this issue, we clarified the expression of desmin and nerve terminal distribution during embryonic development of the LPM in mice.
  
  
  METHODS
  We utilized immunohistochemical staining and reverse transcription chain reaction (RT-PCR) to clarify the expression of desmin and nerve terminal distribution.
  
  
  RESULTS
  We observed weak expression of desmin in the LPM at embryonic day (ED) 11, followed by an increase in expression from embryonic days 12-15. In addition, starting at ED 12, we observed preferential accumulation of desmin in the vicinity of the myotendinous junction, a trend that did not change up to ED 15. Nerve terminal first appeared at ED 13 and formed regularly spaced linear arrays at the centre of the muscle fibre by ED 15. The results of immunohistochemical staining agreed with those of RT-PCR analysis.
  
  
  CONCLUSIONS
  We found that desmin accumulated in the vicinity of the myotendinous junction starting at ED 12, prior to the onset of jaw movement. We speculate that the accumulation of desmin is due to factors other than mechanical stress experienced during early muscle contraction. Meanwhile, the time point at which nerve terminals first appeared roughly coincided with the onset of jaw movement.
authors.affiliation: Department of Anatomy, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan. Electronic address: yamamotomasahito@tdc.ac.jp.
authors.forename: Masahito
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Pharmacology, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shinomiya
authors.affiliation: Department of Anatomy, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan.
authors.forename: Asuka
authors.initials: A
authors.lastname: Kishi
authors.affiliation: Department of Anatomy, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan; Oral Health Science Center hrc8, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yamane
authors.affiliation: Department of Anatomy, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Umezawa
authors.affiliation: Department of Anatomy, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Ide
authors.affiliation: Department of Anatomy, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan; Oral Health Science Center hrc8, Tokyo Dental College, 1-2-2 Masago, Mihama-ku, Chiba City, Chiba 261-8502, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Abe
mesh_terms: D000818:Animals; D003893:Desmin / Q000378:metabolism*; D004210:Dissection; D005260:Female; D007150:Immunohistochemistry; D051379:Mice; D024510:Muscle Development / Q000502:physiology*; D011247:Pregnancy; D011626:Pterygoid Muscles / Q000196:embryology* / Q000294:innervation / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D003893:Desmin
keywords: Desmin; Embryo; Lateral pterygoid; Mouse; Nerve terminal