Acute toxicity studies with quinuronium sulfate in laboratory animals and sheep.

Abstract

The acute toxicity of quinuronium was investigated by measurements of lethal doses (LD50) in mice and rats, cholinesterase activity in vivo in whole blood, and protection from anticholinesterase activity by atropinisation in sheep and rabbits. The LD50s in mice injected i.p. and s.c. were 4.80 and 5.40 mg/kg and in rats 6.3 and 6.5 mg/kg for i.p. and s.c. routes, respectively. Signs of salivation, defecation, anorexia and muscular spasms were observed in sheep. In rabbits anorexia and depression only were observed. There was species variation in normal cholinesterase activity, rabbits being low in activity. Quinuronium inhibited cholinesterase activity from 10 min to 24 h after treatment in sheep by 24% of the normal baseline values. The enzyme activity returned to normal at 48 h. Atropinisation partially protected against anticholinesterase activity in sheep; cholinesterase activity was inhibited by only 14% of the normal baseline values 10 min to 2 h after treatment. This study indicates that quinuronium is highly toxic and that rabbits are moderately resistant