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The Influence of Temperature on the Thick Filaments of Vertebrate Smooth Muscle
Catherine F. Shoenberg
Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Vol. 265, No. 867, A Discussion on Recent Developments in Vertebrate Smooth Muscle Physiology (Mar. 15, 1973), pp. 197-202
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/2417163
Page Count: 9
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When fixation of taenia coli from adult guinea-pigs is initiated at 37 ⚬C only thin filaments and 10 nm filaments are preserved. At 37 ⚬C (i.e. as in vivo) thick filaments are very labile; to preserve them during fixation much thinner muscles must be used such as taenia coli from very young animals. The thick filaments from taenia coli of adult guinea-pigs can however be stabilized by pre-cooling the living muscles before fixation at 37 ⚬C. An ion analysis of these muscles in vivo, and during fixation at 37 and 4 ⚬C, showed that there is a K and Na ion exchange in the tissue both on cooling and during fixation; the exchange is most rapid on fixation particularly when it takes place at 37 ⚬C. The Mg2+ content appears to be unaffected by these conditions, but the Ca2+ content rises both on cooling and during fixation (when the uptake is unexpectedly large). The selective destruction of the cell membrane is greatest when fixation is carried out at 37 ⚬C. It is suggested that pre-cooling may alter thick filaments.
Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences © 1973 Royal Society