Positive inotropic effects of Tityus cambridgei and T. serrulatus scorpion venoms on skeletal muscle

C. R. Borja-Oliveira, T. A. Pertinhez, L. Rodrigues-Simioni, A. Spisni

Research output: Contribution to journalArticlepeer-review


Toxins that block voltage-dependent K+ channels and those that modify Na+ channel gating exhibit positive inotropic effect on skeletal muscle. We compared the effect of the venom of Tityus cambridgei (Tc) and Tityus serrulatus (Ts) scorpions on mouse diaphragm force, in vitro. In indirect and direct (using d-tubocurarine 7.3 μM) stimulation, Tc, 10μg/mL, increased the contractile force, an effect prevented by tetrodotoxin (TTX) while Ts, 0.5 μg/mL, potentiated only indirectly stimulated diaphragm, thus indicating its activity is mainly mediated through acetylcholine release from nerve terminal. This effect is prevented by TTX and attenuated by the K+ channel opener cromakalim. In conclusion, our data show that while the positive inotropic effect of both venoms appears associated to the activity of Na+ and K+ channels, only Tc venom acts also directly on skeletal muscle. This finding call for further studies on Tc venom to identify the toxin responsible for its direct inotropic activity as it may have clinical applications.

Original languageEnglish
Pages (from-to)404-408
Number of pages5
JournalComparative Biochemistry and Physiology - C Toxicology and Pharmacology
Issue number3
Publication statusPublished - Apr 2009


  • Contractile force
  • Cromakalim
  • Mouse phrenic nerve-diaphragm
  • Tetrodotoxin
  • Tityus serrulatus venom

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Physiology
  • Health, Toxicology and Mutagenesis
  • Toxicology


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