Effect of maitotoxin on sea urchin egg fertilization and on Ca2+ permeabilities of eggs and intracellular stores.

Abstract

Maitotoxin (MTX), a potent marine toxin involved in ciguatera poisoning, inhibited sea urchin egg fertilization in a dose-dependent manner with an IC50 of 7.5 x 10(-3) MU (mouse-unit)/ml. It did not affect male gametes fertilizing capabilities but provoked exocytosis in female gametes. It induced a K+ loss simultaneously with a Na+ entry into unfertilized eggs and increased the Ca2+ influx at higher concentrations. On isolated cortex preparations, high concentrations of MTX reduced the rate of ATP-dependent Ca2+ accumulation into reticulum compartments and caused a leakage of Ca2+ from a preparation pre-loaded with 45Ca2+. Verapamil (10(-4) M) similarly blocked the increase of egg permeability to Ca2+ and the effect on Ca2+ sequestering into intracellular compartment, induced by MTX. Ion transport perturbations which evolved relatively slowly are probably not the direct cause of fertilization inhibition which could be related to a modification of the plasma membrane of the female gametes by this hydrophilic toxin.

• Authors: D Pesando, J P Girard, M Durand-Clément, P Payan, S Puiseux-Dao
• Journal: Biology of the cell (Biol Cell) Vol. 72 Issue 3 Pg. 269-73 ( 1991) ISSN: 0248-4900 [Print] England
• PMID: 1794068 (Publication Type: Journal Article)

Chemical References

• Marine Toxins
• Oxocins
• Sodium
• maitotoxin
• Verapamil
• Potassium
• Calcium

Topics

• Animals
• Calcium (metabolism)
• Cell Membrane Permeability
• Dose-Response Relationship, Drug
• Endoplasmic Reticulum (drug effects, metabolism)
• Fertilization (drug effects)
• In Vitro Techniques
• Kinetics
• Male
• Marine Toxins (isolation & purification, pharmacology)
• Ovum (drug effects, physiology)
• Oxocins
• Potassium (metabolism)
• Sea Urchins
• Sodium (metabolism)
• Spermatozoa (drug effects, physiology)
• Verapamil (pharmacology)