MALFORMATIONS OF THE CENTRAL NERVOUS SYSTEM INDUCED BY NEUROTROPIC DRUGS IN MOUSE EMBRYOS

Out of a sample of fifteen neurotropic drugs consisting of seven antidepressants and anti-psychotics, two antianxiety drugs, one anticonvulsant, three opiates and two synthetic analgesics, twelve were found to be teratogenic for mouse embryos, causing malformations of the central nervous system. After single injections of the teratogenic dose administered at the very beginning of the ninth day of gestation, four days later, i.e. in 13-day-old embryos, the induced defects appeared to make up a recurring syndrome of malformations which consists of several abnormalities present in various frequencies either individually or in combination in the same embryos. These malformations are: exencephaly, craniorachischisis, cervical and thoraco-lumbar myeloschisis, hydrocephalic dilatation of the fourth brain ventricle, Z-shaped kinking of the spinal cord and lumbar hydromyelia. In addition, after administration of some of the drugs, branchyury or anury with or without lumbar myeloaplasia were recorded. In general the results reported here seem to suggest that because of their possible affinity neurotropic drugs are potentially teratogenic for the embryonic central nervous system if applied at the time of the neural tube closure although it is known that there are drugs in this group which do not cause any malformations of the central nervous system and that many non-neurotropic agents do cause such malformations. Secondly, the results seem to suggest also that the position of the malformations along the cerebro-spinal axis may be depending to some extent on the pharmacological properties of the drugs tested. These conjectures are treated here as entirely provisional pending further investigations.