Anatoxin-a(s), an anticholinesterase from the cyanobacterium Anabaena flos-aquae NRC-525-17

Toxicon. 1987;25(11):1221-7. doi: 10.1016/0041-0101(87)90140-1.

Abstract

Anatoxin a(s) [antx-a(s)] given intraperitoneally to Sprague-Dawley rats at different doses (0.1-1.0 mg/kg) caused signs of severe cholinergic overstimulation. Assays of rat blood acetylcholinesterase (AChE) revealed a dose-dependent inhibition. The in vitro inhibition of electric eel acetylcholinesterase (AChE, E.C. 3.1.1.7) and horse serum butyrylcholinesterase (BUChE, E.C. 3.1.1.8) by antx-a(s) was time- and concentration-dependent. The inhibition of electric eel AChE follows first order kinetics, indicative of irreversible inhibition. The irreversibility of electric eel AChE inhibition was confirmed by a plot of Vmax versus total enzyme concentration [ET]. The kinetics of inhibition of cholinesterase by antx-a(s) supports the previous pharmacological findings that antx-a(s) is an anticholinesterase and that signs of intoxication by it are primarily due to cholinesterase inhibition.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bacterial Toxins*
  • Binding, Competitive / drug effects
  • Butyrylcholinesterase / metabolism
  • Cholinesterase Inhibitors* / isolation & purification
  • Cyanobacteria / enzymology*
  • Cyanobacteria Toxins
  • Electrophorus
  • Horses
  • Kinetics
  • Male
  • Marine Toxins / isolation & purification
  • Marine Toxins / pharmacology*
  • Microcystins
  • Rats
  • Rats, Inbred Strains
  • Tropanes

Substances

  • Bacterial Toxins
  • Cholinesterase Inhibitors
  • Cyanobacteria Toxins
  • Marine Toxins
  • Microcystins
  • Tropanes
  • anatoxin a
  • Butyrylcholinesterase