Calcium sensitizing action of carnosine and other endogenous imidazoles in chemically skinned striated muscle

J Physiol. 1992 Aug;454:421-34. doi: 10.1113/jphysiol.1992.sp019271.


1. The imidazole-containing compounds carnosine and homocarnosine, endogenous to skeletal and cardiac muscle, have been tested for effect on the contractile behaviour of chemically skinned (saponin or Triton X-100) skeletal and cardiac muscle. 2. Carnosine, at millimolar concentrations which are near physiological for many skeletal fibres, and in a concentration-dependent fashion, shifts the curve relating [Ca2+] to steady-state tension to lower [Ca2+] in both skeletal (frog but not crab) and cardiac (rat) muscle preparations. 3. Of other imidazoles endogenous to heart, homocarnosine is somewhat more effective, while N-acetyl L-histidine is much less so. 4. The maximum level of Ca(2+)-activated force is increased significantly by homocarnosine in cardiac trabeculae. 5. We propose that the cellular imidazoles related to carnosine are natural 'Ca2+ sensitizers' in striated muscle. Alterations in their levels as a result of disease or training, and between different fibre types, may contribute to differences in contractile performance of the intact tissues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brachyura
  • Caffeine / pharmacology
  • Calcium / metabolism*
  • Carnosine / pharmacology*
  • Heart / physiology
  • Histidine / analogs & derivatives
  • Histidine / pharmacology
  • Imidazoles / pharmacology*
  • In Vitro Techniques
  • Muscle Contraction / drug effects*
  • Muscle Contraction / physiology
  • Muscles / drug effects
  • Muscles / metabolism
  • Muscles / physiology
  • Myocardial Contraction / drug effects*
  • Myocardial Contraction / physiology
  • Rana temporaria
  • Rats
  • Xenopus laevis


  • Imidazoles
  • Caffeine
  • Histidine
  • Carnosine
  • N-acetylhistidine
  • Calcium