[Anticholinesterase agents and axial teratogenesis in quail embryos]

The results of an investigation made with organo-phosphorous compounds (OP), carbamates (C), and a compound including oxamide groups (GO), indicate that spine anomalies in Japanese quail embryos are linked with cholinesterase inhibition. The blocking effect of these various compounds on cholinesterases has been examined both in vitro and in vivo.In vitro, the embryonic cholinesterases are particularly sensitive to carbamates, whereas high concentrations of organo-phosphorous compounds-and especially those which need to be activated at the level of metabolism-block only part of the relevant activities of the enzyme.In vivo, among the products examined, only malathion (OP) and ambenonium (GO) were found to be inactive (or having little effect) so far as cholinesterases are concerned. Although they appeared rather strongly embryotoxic, these two poisons did not prove teratogenic. A strong inhibition of cholinesterase activities was noticed in all cases, when applying the other compounds at teratogenic doses.The close relationship between the inhibition of cholinesterases and the appearance of axial abnormalities is confirmed by using increasing doses of parathion (OP) and neostigmine (C).Beak and leg malformations were brought about only by dicrotophos and eserine, and did not prove to be linked with cholinesterase inhibition, since they were not observed with compounds having a high activity towards these enzymes, such as parathion (OP), neostigmine (C) and demecarium (C).