[The effect of hypertonic solutions on contracture of a tonic muscle fiber].
Effect of glycerol, sucrose and NaC1 hypertonic solutions exerted on potassium contracture and resting membrane potential in isolated frog tonic muscle fibres were studied. Sucrose and NaC1 hypertonic solutions induce a stable depolarization and depress potassium contracture, while glycerol results in a transient depolarization followed by recovery of resting membrane potential and contracture reactions. The removal of 400 mM glycerol induces an insignificant depolarization and disappearance of contracture reactions, however, after the removal of sucrose of NaC1 hypertonicity both the parameters tend to restore. The isolated phasic and tonic fibres lose irreversibly potassium contracture reactions after the removal of 100 mM and 400 mM glycerol, respectively, the latter being more resistant to this procedure. Nevertheless it is concluded that the T-system is equally important for excitation--contraction coupling in tonic and in phasic fibres.
D000818:Animals; D005990:Glycerol / Q000494:pharmacology*; D006982:Hypertonic Solutions / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects*; D011188:Potassium / Q000494:pharmacology; D011896:Rana temporaria; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*; D013395:Sucrose / Q000494:pharmacology*
D006982:Hypertonic Solutions; D012462:Saline Solution, Hypertonic; D012965:Sodium Chloride; D013395:Sucrose; D005990:Glycerol; D011188:Potassium
Vliianie gipertonicheskikh rastvorov na kontrakturu tonicheskogo myshechnogo volokna