Spontaneous gelatinization of sarcoplasmic proteins of skeletal and smooth muscles and possible relation of this phenomenon to developmental mechanism of plastic tonus

Article type: Research Article

Authors: Ivanov, I.I. | Golikova, A.I.^{; *}

Affiliations: Institute of Experimental Medicine, Academy of Medical Sciences of U.S.S.R. and Institute of Cytology, Academy of Sciences of U.S.S.R., Leningrad, U.S.S.R.

Note: [*] L.M. Belyavtseva and I.M. Matveeva took part in the experiment at the first stage of this work. The preliminary results of this part of the investigation were delivered at the FEBS 7th Meeting (Varna, September 1971) and then published as abstracts of the 7th Meeting (I.I. Ivanov, L.M. Belyavtseva and I.M. Matveeva, abstracts 7th Meeting, FEBS, 799, p. 281).

Abstract: The grinding of minced muscle tissue with quartz sand followed by extraction of the resulting homogeneous mass with NaCl solution of low ionic strength (0.05) in ratio 1:2 leads to formation of extracts undergoing rapidly spontaneous gelatinization during storage. The strength (viscosity) of the gels formed was studied by the “falling ball” method and Weiler and Rhebinder’s method of tangential shear of plate. The effect of various factors such as temperature, Ca ions, ATP, ethyleneglycoldiamintetracetate (EGTA) was studied and in some instances estimated quantitatively. It was shown that Ca ion binding by the sarcoplasmic reticulum or EGTA was accompanied by conversion of the sarcoplasmic proteins solution into solid gel. It is suggested that this phenomenon underlies the development of the smooth muscle catch function, “viscous after-effect” and tonic hardening of vertebrate skeletal muscles during catalopsy. This concept does not contradict Lowy and Hanson’s hypothesis according to which the development mechanism of the catch function is due to the fact that after cessation of active contraction linkages between thick and thin filaments are either locked in the attached state or they detach very slowly. It appears that both these mechanisms may co-exist and possibly supplement each other.

DOI: 10.3233/BIR-1973-10102

Journal: Biorheology, vol. 10, no. 1, pp. 7-16, 1973