A comparison of the mechanical properties of oesophageal striated muscle with skeletal muscles of the guinea pig
Wareham, A.C.; Whitmore, I.
Pflugers Archiv European Journal of Physiology 395(4): 312-317
1982
ISSN/ISBN: 0031-6768 PMID: 6218476 Document Number: 184228
An in vitro comparative study was made of the contractile properties of guinea pig esophageal striated muscle with fast twitch (extensor digitorum longus) and slow twitch (soleus) muscles. Histochemical analysis of sections showed esophageal fibers to react in a manner typical of fast twitch muscles. Isometric measurements made at 23.degree. and 37.degree. C indicated that esophageal striated muscle contracts at speeds similar to, but still significanlty faster than, soleus. Isotonic measurements of esophageal preparations made at 23.degree. C gave an intrinsic speed of shortening and an a/Po [a = constant, Po = isometric tension] value derived from Hill's equation, comparable with that obtained for soleus. The reason for the contraction between the results from histochemistry and the results from isometric and isotonic contractions are not apparent but may be due to differences in fiber arrangement between esophagus and the 2 skeletal muscles.