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THE SARCOPLASMIC RETICULUM AND T‐SYSTEM OF RAT EXTENSOR DIGITORUM LONGUS MUSCLES EXPOSED TO HYPERTONIC SOLUTIONS
Author(s) -
Davey DF,
O'Brien GM
Publication year - 1978
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1978.46
Subject(s) - endoplasmic reticulum , tonicity , extensor digitorum muscle , extensor digitorum longus muscle , anatomy , medicine , biology , microbiology and biotechnology , skeletal muscle , soleus muscle
Excised rat extensor digitorum longus muscles were soaked in a Krebs solution made hypertonic with extra NaCl and fixed using a combination of acrolein and glutaraldehyde dissolved in the same hypertonic Krebs. Electron microscopic examination showed that the sarcoplasmic reticulum (S.R.) of these muscles occupied the same fraction of fibre volume as it did in control muscles soaked and fixed in normal Krebs solution, contradicting previous studies on frog muscle. It appears unlikely that the S.R. is the rapidly exchanging Na+-compartment of rat muscle which enlarges in hypertonic solutions, or that it is an extracellular compartment. The T-system of hypertonic muscles was swollen, but its volume is insufficient to form the rapidly exchanging Na+-compartment.