K. Husain et al., ACUTE TOXICITY OF SYNTHETIC GYMNODINIUM BREVE TOXIN METABOLITE AND ITS ANALOGS IN MICE, Ecotoxicology and environmental safety, 35(1), 1996, pp. 77-80
Acute toxicity of synthetic Gymnodinium breve toxin metabolite and its
analogues has been investigated in mice. The anticholinesterase poten
cies of the toxin metabolite and its analogues were determined in vitr
o as well as in vivo. The intraperitoneal LD(50) of the parent metabol
ite ethyl-2-oxopropylidene)phosphorohydrazidothioate(E )oxime in mice
was higher compared to LD(50) values of its analogues. The in vitro ac
etylcholinesterase (AChE)-inhibiting potency values were higher for di
ethoxy(P=O) analogue than for diispropoxy(P=O) analogue. Lethal doses
of parent metabolite and its analogues significantly inhibited AChE ac
tivity in the blood and brain of mice 1 hr postexposure. The maximum i
nhibition by the parent metabolite was observed in both tissues. The p
ercentage inhibition of AChE activity was greater in the blood than in
the brain. The results indicate that these agents have anticholineste
rase action specifically in the blood. In conclusion, the parent toxin
metabolite is a more potent inhibitor of AChE in vivo, whereas higher
toxicity is associated with other analogues, suggesting the involveme
nt of other factors influencing the toxicity, which needs to be furthe
r investigated. (C) 1996 Academic Press, Inc.