HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 290/5/C1446    most recent 00323.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Bergrin, M. Articles by Reiser, P. J. Search for Related Content PubMed PubMed Citation Articles by Bergrin, M. Articles by Reiser, P. J.

REPORT

MUSCLE CELL BIOLOGY AND CELL MOTILITY

Three-dimensional compartmentalization of myosin heavy chain and myosin light chain isoforms in dog thyroarytenoid muscle

¹Department of Oral Biology, College of Dentistry, The Ohio State University, Columbus, Ohio; and ²Department of Physiology, University of Sydney, New South Wales, Australia

Submitted 4 July 2005 ; accepted in final form 6 December 2005

ABSTRACT

The thyroarytenoid muscle, a vocal fold adductor, has important roles in airway protection (e.g., prevention of aspiration) and phonation. Isoform expression of myosin heavy chain (MHC), a major determinant of muscle-shortening velocity, has been reported to be heterogeneous in this muscle in several mammals, differing markedly between the medial and lateral divisions. The objective was to determine the isoform expression patterns of both MHC and myosin light chain (MLC), with the latter having a modulatory role in determining shortening velocity, to further test whether the expression of both myosin subunits differs in multiple specific sites within the divisions of the dog thyroarytenoid muscle, potentially revealing even greater compartmentalization in this muscle. Our results indicate the existence of large gradients in the relative levels of individual MHC isoforms in the craniocaudal axis along the medial layer (i.e., airflow axis), where levels of MHC-I and MHC-IIA are low at both ends of the axis and high in the middle and MHC-IIB has a reciprocal distribution. The lateral layer is more uniform, with high levels of MHC-IIB throughout. The level of MHC-IID is relatively constant along the axis in both layers. Large differences exist in the distribution of MHC isoforms among single fibers isolated from sites along the craniocaudal axis, especially in the lateral layer. Systematic regional variations are apparent in the MLC isoform composition of single fibers as well, including some MLC isoform combinations that are not observed in dog limb muscles. Variations of MHC and MLC isoform expression in the dog thyroarytenoid muscle are greater than previously recognized and suggest an even broader range of contractile properties within this multifunctional muscle.

intrinsic laryngeal muscle; airway protection; vocalization

This article has been cited by other articles:

				L. Toniolo, P. Cancellara, L. Maccatrozzo, M. Patruno, F. Mascarello, and C. Reggiani Masticatory myosin unveiled: first determination of contractile parameters of muscle fibers from carnivore jaw muscles Am J Physiol Cell Physiol, December 1, 2008; 295(6): C1535 - C1542. [Abstract] [Full Text] [PDF]

				L. Toniolo, L. Maccatrozzo, M. Patruno, E. Pavan, F. Caliaro, R. Rossi, C. Rinaldi, M. Canepari, C. Reggiani, and F. Mascarello Fiber types in canine muscles: myosin isoform expression and functional characterization Am J Physiol Cell Physiol, May 1, 2007; 292(5): C1915 - C1926. [Abstract] [Full Text] [PDF]