Korean J Otolaryngol-Head Neck Surg.  2000 Mar;43(3):300-305.

Quantitative Analysis of Myosin Heavy Chain (MHC) mRNA expression in Thyropharyngeus muscle and Cricopharyngeus muscle in Rats

• Park YS
• Jung HH
• Nam SY

Abstract

BACKGROUNDS: The inferior pharyngeal constrictor muscle (IPC), which consists of the thyropharyngeus (TP) and cricopharyngeus (CP) muscles, plays an important role during deglutition, but their function is different when analysed by radiographic, manometric and electromyographic studies.
OBJECTIVES
AND MATERIALS: The purpose of this study is to quantify the expression levels of MHC mRNA isoforms (2B, 2X, 2A, 2L, beta-cardiac, neonatal and embryonic) in thyropharyngeus and cricopharyngeus muscles of rats using competitive PCR.
RESULTS
The thyropharyngeus muscle was mainly consisted of three fast-twitching MHC isoforms, mostly 2X isoform (85.2%). On the other hand, the cricopharyngeus muscle contained two-third of fast-twitching isoforms(65.1%) and one-third of neonatal MHC(34.9%).
CONCLUSIONS
The thyropharyngeus muscle could be characterized as a fast-twitching muscle and the cricopharyngeus muscle is probably considered as a sarcomeric regenerating muscle that is caused by frequently mechanical damage on deglutition.

Keyword

Competitive PCR; gene expression; thyropharyngeus muscle; cricopharyngeus muscle; rat

MeSH Terms

Animals
Deglutition
Gene Expression
Hand
Muscles
Myosin Heavy Chains*
Myosins*
Pharyngeal Muscles*
Polymerase Chain Reaction
Protein Isoforms
Rats*
RNA Isoforms
RNA, Messenger*
Myosin Heavy Chains
Myosins
Protein Isoforms
RNA Isoforms
RNA, Messenger