Porphyrin induced calcium release from skeletal muscle sarcoplasmic reticulum

Arch Biochem Biophys. 1993 Mar;301(2):396-403. doi: 10.1006/abbi.1993.1162.

Abstract

Micromolar concentrations of the porphyrin mesotetra(4-N-methylpyridyl)porphine tetraiodide is shown to induce rapid release of Ca2+ from skeletal muscle sarcoplasmic reticulum vesicles. Porphyrin-induced Ca2+ release is stimulated by ATP (KdATP = 100 microM) and Ca2+ (KdCa = 1 microM) and is inhibited by Mg2+ (KI = 220 microM) and ruthenium red (KI = 7 nM). The porphyrin is also shown to stimulate high affinity [3H]ryanodine binding by decreasing the dissociation constant (kd) and increasing the binding capacity (Bmax). Moreover, in the presence of Mg2+, receptor binding is sensitized to activation by Ca2+, and porphyrin-stimulated channel activity is sensitized to activation by Ca2+. These observations show that porphyrin-induced Ca2+ release is due to a direct interaction with the Ca2+ release protein from sarcoplasmic reticulum.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / analogs & derivatives
  • Adenosine Triphosphate / pharmacology
  • Animals
  • Caffeine / pharmacology
  • Calcium / metabolism*
  • Calcium Channels / drug effects
  • Calcium Channels / metabolism*
  • Dithiothreitol / pharmacology
  • Magnesium / pharmacology
  • Mesoporphyrins / pharmacology*
  • Porphyrins / pharmacology*
  • Rabbits
  • Ruthenium Red / pharmacology
  • Ryanodine / metabolism
  • Sarcoplasmic Reticulum / drug effects
  • Sarcoplasmic Reticulum / metabolism*

Substances

  • Calcium Channels
  • Mesoporphyrins
  • Porphyrins
  • Ruthenium Red
  • Ryanodine
  • 5'-adenylyl (beta,gamma-methylene)diphosphonate
  • tetra(4-N-methylpyridyl)porphine
  • Caffeine
  • Adenosine Triphosphate
  • Magnesium
  • alpha,beta-methyleneadenosine 5'-triphosphate
  • Calcium
  • Dithiothreitol