Inositol trisphosphate stimulates calcium release from peeled skeletal muscle fibers

Sue K. Donaldson, Nelson D. Goldberg, Timothy F. Walseth, Daniel A. Huetteman

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


The effects of inositol phosphates (tris (InsP3), bis (InsP2), mono (InsP)) on rabbit adductor magnus and soleus muscles were determined using mechanically peeled fibers (sarcolemma removed). Isometric force generation of each fiber was continuously monitored and was used along with 45Ca to detect calcium release from internal fiber stores. All experiments were conducted at a physiological Mg2+ concentration (10-3 M) of the bathing solutions. The inositol phosphates did not directly activate the contractile apparatus. At bath concentrations of 100-300 μM, only InsP3 was capable of stimulating Ca2+ release. In contrast, 1 μM InsP3 maximally and selectively stimulated Ca2+ release when microinjected into the myofilament lattice. Calcium releasing effects of InsP2 and InsP were manifested at 10 μM when they were microinjected. The end-to-end internal Ca2+ release and subsequent fiber force generation stimulated by the locally applied microinjected InsP3 suggests that the InsP3-induced Ca2+ release mechanism may involve propagation, but not via the Ca2+-induced Ca2+ release, since procaine did not inhibit this response. These findings support the possibility that InsP3 plays a role in skeletal muscle excitation-contraction coupling.

Original languageEnglish (US)
Pages (from-to)92-99
Number of pages8
JournalBBA - Molecular Cell Research
Issue number1
StatePublished - Jan 19 1987

Bibliographical note

Funding Information:
We thank Coral Sampson for typing the manuscript, Dr. Michael Berridge for the InsP 3 sample, Dr. Philip Best for assistance in developing the 45Ca bubble technique and The National Institutes of Health for research grants (AM 35132, GM 28818).


  • (Skinned rabbit muscle fiber)
  • Ca release
  • Excitation-contraction coupling
  • Inositol trisphosphate
  • Sarcoplasmic reticulum
  • Skeletal muscle


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