Effects of yessotoxin (YTX) on the skeletal muscle: an update

Abstract

Yessotoxins (YTXs) are algal toxins originally included in the diarrheic toxins. After oral intake, YTXs induce only ultra-structural changes (packages of swollen mitochondria) in cardiac cells. The aim of this study was to investigate the possible effects of YTX on the other contractile striated tissue, the skeletal muscle, in vitro and in vivo. In vitro, in skeletal mouse myotubes, YTX (0.01–1.0 ;µM) influenced cell excitability in a concentration- and time-dependent way. In the in vivo study, transmission electron microscopy analysis did not reveal any ultra-structural alteration of skeletal muscle after acute (1 ;mg ;kg⁻¹) or repeated (1 and 2 ;mg ;kg⁻¹ ;day⁻¹, for 7 days) oral administration of YTX to mice. The observation that effects were detected in vitro but not in vivo supports the hypothesis of a low YTX bioavailability to skeletal muscle after oral intake. Therefore, the results seem to exclude a toxic effect in skeletal muscle when YTX is consumed as a food contaminant.

Keywords:

• yessotoxin
• skeletal muscle cells
• calcium
• videomicroscopy
• transmission electron microscopy

Acknowledgements

This work was supported by a grant of the Italian Ministry of Instruction, University and Research. The authors are grateful to Professor Roberto Della Loggia (University of Trieste, Italy) for stimulating discussions, and to Mr Claudio Gamboz, Centro Coordinamento e Sviluppo Progetti e Apparecchiature–CSPA, University of Trieste, for careful technical work.