Striated scallop muscle relaxation: fast force transients produced by photolysis of Diazo-2

Biochem Biophys Res Commun. 1990 Apr 16;168(1):295-300. doi: 10.1016/0006-291x(90)91707-y.

Abstract

Relaxation of the myosin regulated striated adductor muscles of Pecten maximus was initiated by the photolysis of the caged Ca2+ chelator, Diazo-2. The fibres relaxed to approximately 30% of the maximum tension with a mean half-time of 17.9 +/- 1.6 ms (n = 7, temp 12 degrees C), much faster than the rates observed in intact muscle at the same temperature. This indicates that in the intact adductor muscle the slower relaxation rate is determined by the speed of Ca2+ removal from the sarcoplasm. The faster rate of relaxation of scallop muscle in vitro, compared with frog skeletal muscle may reflect different mechanisms of regulation of the crossbridge cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / physiology*
  • Chelating Agents / pharmacology
  • Diazonium Compounds
  • In Vitro Techniques
  • Kinetics
  • Mollusca
  • Muscle Contraction*
  • Muscle Relaxation*
  • Phenoxyacetates
  • Photochemistry

Substances

  • Chelating Agents
  • Diazonium Compounds
  • Phenoxyacetates
  • diazo-2
  • Calcium