Polyamines decrease Ca2+ sensitivity of tension and increase rates of activation in skinned cardiac myocytes

Samantha - Harris, Jitandrakumar R. Patel, Laurence J. Marton, Richard L. Moss

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Owing in part to their interactions with membrane proteins, polyamines (e.g., spermine, spermidine, and putrescine) have been identified as potential modulators of membrane excitability and Ca2+ homeostasis in cardiac myocytes. To investigate whether polyamines also affect cardiac myofilament proteins, we assessed the effects of polyamines on contractility using rat myocytes and trabeculae that had been permeabilized with Triton X-100. Spermine, spermidine, and putrescine reversibly increased the [Ca2+] required for half-maximal tension (i.e., right-shifted tension pCa curves), with the following order of efficacy: spermine (+4) > spermidine (+3) > putrescine (+2). However, synthetic analogs that differed from spermine in charge distribution were not as effective as spermine in altering isometric tension. None of the polyamines had a significant effect on maximal tension, except at high concentrations. After flash photolysis of DM-Nitrophen (a caged Ca2+ chelator), spermine accelerated the rate of tension development at low and intermediate but not high [Ca2+]. These results indicate that polyamines, especially spermine, interact with myofilament proteins to reduce apparent Ca2+ binding affinity and speed cross-bridge cycling kinetics at submaximal [Ca2+].

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume279
Issue number3 48-3
StatePublished - 2000
Externally publishedYes

Fingerprint

Spermine
Polyamines
Cardiac Myocytes
Putrescine
Spermidine
Myofibrils
Photolysis
Octoxynol
Chelating Agents
Membrane Potentials
Muscle Cells
Membrane Proteins
Proteins
Homeostasis

Keywords

  • Cardiac muscle
  • Myofilaments
  • Spermine

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Polyamines decrease Ca2+ sensitivity of tension and increase rates of activation in skinned cardiac myocytes. / Harris, Samantha -; Patel, Jitandrakumar R.; Marton, Laurence J.; Moss, Richard L.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 279, No. 3 48-3, 2000.

Research output: Contribution to journalArticle

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