[Lanthanum and scorpion venom on the isolated guinea pig ileum].

In the guinea-pig isolated ileum, lanthanum increases the quantity of spontaneously released acetylcholine and induces contracture of this muscle. We have shown that the latter phenomenon is not a consequence of the former. We conclude that it could be due to the Ca++ displaced by La+++. The scorpion venom effects are abolished by lanthanum. We explain this observation by blockage of Ca++ fluxes.