Behavioral Teratogenesis: An Extension to the Teratogenesis of Functions

Abstract

Major malformations correspond to pathology during the first 2 months of gestation. Thereafter, histological and biochemical abnormalities can result from different negative maternal incidents and, without obvious malformations, change the phenotype of the conceptus. These abnormalities lead to essentially functional disorders often compatible with life and to more or less serious handicaps. All systems, when they arrive at such a stage of development, can be theoretically involved. The central nervous system (CNS) offers a very clear example of such weaknesses because its maturation is particularly long and susceptible to changes even after birth. The steps of this maturation overlap and form a continuum reflected in the pathology. Mental retardation occurring in children born of mothers who were subjected to atomic radiation, or ingested methylmercury from industrial waste, or who suffered the effects of lead, alcohol or tobacco constitutes a clear clinical example. Animal experiments confirm these data, adding pathogenic explanations. These experiments also explore the possible consequences that some medical techniques such as modern reproductive technology, for example embryo freezing, can have on the development of the conceptus. Toxic substances or drugs can also be responsible for such abnormalities through a genetic attack on spermatogenesis. Behavioral teratogenesis also opens a larger persepective related to the optimal quality of the conceptus and the determining factors, from stress or dietary factors during apparently normal pregnancy to paternal age at the moment of conception. Finally, given that other systems than the CNS can be involved in histological or biochemical abnormalities, such as the reproductive system, we must ask what other types of functional pathology can be induced by interventions on gametes, the embryo and the fetus. Thus, behavioral teratogenesis leads to the teratogenesis of functions.

Embryo cryopreservation and development: facts, questions and responsibility

“…This suggested the possibility of a still undetected genotoxic potential; (iii) assessment of post-natal development after embryo cryopreservation has mainly focused on patent anomalies at birth or in early life, and has not been carried out on adult and senescent individuals. However, many mutations can have mild or delayed phenotypic effects, and numerous clinical and experimental observations show that developmental disturbances can respect viability and macromorphological appearance while altering physiological processes, including behaviour and cognitive functions, through biochemical or microstructural anomalies (Auroux, 1997). Besides classic morphological examination, neural and behavioural screening has been recommended, for instance, by the National Institutes for Mental Health (NIMH), for transgenic and knock-out mice.…”

“…We also wanted to compare the intensity of eventual effects of cryopreservation with that of genotype-related differences. Similarly, sex-related differences have been documented in various situations (Auroux, 1997). So, in our experiment three main factors, genotype, sex and cryopreservation, were considered and various tests or evaluations were performed at different periods up to 67 weeks of age.…”

Het belang van de prenatale levensfase voor de ontwikkeling van psychopathologie

“…Om een aantal misverstanden uit de weg te ruimen is het volgens Auroux (1997) essentieel dat men inziet dat het verschil tussen 'misvormingen' (zichtbare verandering van de vorm of de structuur') en 'functionele veranderingen of stoornissen' alleen gebaseerd is op een verschil in de schaal (het niveau) van observatie. Vervormingen van microstructuren -bijvoorbeeld synapsen van neuronen, of een wijziging in het aantal receptoren voor bepaalde hormonen -die met het blote oog niet waarneembaar zijn, zou men vroeger niet aangeduid hebben als een 'misvorming' van het zenuwstelsel en een stof die deze vervorming veroorzaakt herkende men niet als een teratogeen.…”

Prenatal Exposures to LTP-Patterned Magnetic Fields: Quantitative Effects on Specific Limbic Structures and Acquisition of Contextually Conditioned Fear

“…Alterations in the neuronal organization of limbic structures, which might underlie these behavioral changes, may also result from CMF exposure. Such effects are most probable when the organism is exposed during the prenatal or perinatal period and when the nervous system is undergoing rapid development and is vulnerable even to subtle stimuli (Auroux, 1997).…”