Authors: Chen, E-KWAN; Dutta, Hiran M.

Source: Netherlands Journal of Zoology, Volume 42, Number 1, 1991 , pp. 101-127(27)

Publisher: BRILL

Abstract:

The distribution of muscle fiber types and their electrical properties in subdivisions of the masticatory muscles in guinea pigs were individually investigated. Myosin ATPase, phosphorylase, and succinic dehydrogenase, were used to determine the types of muscle fiber. All the masticatory muscles consist of three fiber types (FOG, FG, and SO). However, the ratios of muscle fiber types in each masticatory muscle and in the subdivisions of the same muscle differ. Differences in the duration and the onset of electromyographic activity were determined for the same subdivisions of these muscles analyzed histochemically. The predominant active muscles are found always on one side during the entire cycle. It was found that in the case of the masseter the ipsilateral opening (working) muscles fire first, followed by the firing of the ipsilateral closing (balancing) muscles. In working muscle, the duration is longer and the level of electric activity is higher than in those of the balancing side. Both symmetric and asymmetric activities were found in deep masseters. The study reveals that in guinea pigs, the distribution of muscle fibers and their activity pattern vary among subdivisions of m. masseter, m. digastricus, and m. temporalis. The differences in regional muscular activity reflect differences in the fiber composition.

Keywords: guinea pig; histochemistry; electromyography

Document Type: Research article

DOI: http://dx.doi.org/10.1163/156854292X00053

Affiliations: 1: (University of Illinois Medical Center, Chicago, Illinois 60660 and Department of Biological Sciences, Kent State University Kent, Ohio 44242

Publication date: 1991-01-01

More about this publication?

• For more content see: Archives Néerlandaises de Zoologie (Volumes 1-17), Animal Biology (Volume 53 onwards)

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