title: Histochemical study of rabbit medial pterygoid muscle during postnatal development.
abstract: The medial pterygoid muscle is a layered structure like the masseter muscle. This study aimed at investigating the regional differences in fiber type composition and fiber diameter of the medial pterygoid muscle in the rabbit from birth until 33 weeks of age. Histochemical analysis of the medial pterygoid muscle was performed during five developmental stages (4, 9, 12, 18, and 33 weeks after birth) in 30 male Japanese white rabbits. Six fiber types (I, IC, IIC, IIA, IIAB, and IIB) were identified by mATPase staining. An increase in diameter was observed in fiber types I and IC until 9 weeks of age, and in fiber types IIC, IIA, IIAB, and IIB until 33 weeks of age. No significant differences in fiber diameter were noted in the different regions of the pterygoid muscle. Moderate fast to slow fiber type shifts occurred from weeks 4-12; thereafter, a rapid slow to fast fiber type shift was observed. Significant differences in fiber type composition based on regional differences were noted at 4 weeks of age. However, there was no difference in fiber type composition between regions at 33 weeks. In conclusion, it was clear that the diameter and proportion of fast fibers had increased even after reaching sexual maturity in rabbits. In addition, the medial pterygoid muscle tissues appeared to be homogenous at 33 weeks of age with very few differences between regions.
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya, 464-8651, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Physiology, School of Dentistry, Aichi-Gakuin University, Kusumoto-cho 1-100, Chikusa-ku, Nagoya, 464-8650, Japan. takumi@dpc.agu.ac.jp.
authors.forename: Takumi
authors.identifier: http://orcid.org/0000-0003-3953-5961
authors.initials: T
authors.lastname: Morita
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya, 464-8651, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takasu
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya, 464-8651, Japan.
authors.forename: Kozue
authors.initials: K
authors.lastname: Kuroki
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya, 464-8651, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Department of Physiology, School of Dentistry, Aichi-Gakuin University, Kusumoto-cho 1-100, Chikusa-ku, Nagoya, 464-8650, Japan.
authors.forename: Katsunari
authors.initials: K
authors.lastname: Hiraba
authors.affiliation: Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, Suemori-dohri 2-11, Chikusa-ku, Nagoya, 464-8651, Japan.
authors.forename: Shigemi
authors.initials: S
authors.lastname: Goto
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D008297:Male; D011626:Pterygoid Muscles / Q000254:growth & development*; D011817:Rabbits
keywords: Histochemistry; Medial pterygoid muscle; Muscle fiber type; Postnatal development; Rabbits