Different isometric force - [Ca2+] relationships in slow and fast twitch skinned muscle fibres of the rat.
Skinned muscle fibres prepared from fast and slow twitch muscles of rat have been activated in Ca2+-buffered solutions using a new activation procedure (Moisescu, D.G. and Thieleczek, R. (1978) J. Physiol. 275, 241--262). The results indicate that (i) the Ca2+ activation curve is less steep for slow fibres, (ii) physiologically relevant force levels are attained considerably faster at constant [Ca2+] in fast fibres, and (iii) active force becomes noticeable at lower [Ca2+], but reaches saturation at higher [Ca2+] for slow fibres.
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D051381:Rats
D002118:Calcium