Cytochemical comparison of two kinds of experimental hypoxia: changes of RNA content per cell in cerebellar and cerebral cortex neurons and perineuronal glia

Structural Effects and Neurofunctional Sequelae of Developmental Exposure to Psychotherapeutic Drugs: Experimental and Clinical Aspects

The advent of psychotherapeutic drugs has enabled management of mental illness and other neurological problems such as epilepsy in the general population, without requiring hospitalization. The success of these drugs in controlling symptoms has led to their widespread use in the vulnerable population of pregnant women as well, where the potential embryotoxicity of the drugs has to be weighed against the potential problems of the maternal neurological state. This review focuses on the developmental toxicity and neurotoxicity of five broad categories of widely available psychotherapeutic drugs: the neuroleptics, the antiepileptics, the antidepressants, the anxiolytics and mood stabilizers, and a newly emerging class of nonprescription drugs, the herbal remedies. A brief review of nervous system development during gestation and following parturition in mammals is provided, with a description of the development of neurochemical pathways that may be involved in the action of the psychotherapeutic agents. A thorough discussion of animal research and human clinical studies is used to determine the risk associated with the use of each drug category. The potential risks to the fetus, as demonstrated in well described neurotoxicity studies in animals, are contrasted with the often negative findings in the still limited human studies. The potential risk fo the human fetus in the continued use of these chemicals without more adequate research is also addressed. The direction of future research using psychotherapeutic drugs should more closely parallel the methodology developed in the animal laboratories, especially since these models have already been used extremely successfully in specific instances in the investigation of neurotoxic agents.

An attempt to influence DNA content in postmitotic Purkinje cells of the cerebellum

Feulgen-DNA content has been measured cytophotometrically in granule and Purkinje cells of the rat and mouse cerebellum. The study has confirmed that under normal conditions a very small part of the P. cell population in rats (less than 3%) possesses a Feulgen-DNA surplus ranging from 2C to 4C. In mice, the hyperdiploid (H2C) P. cells are even more rare. The occurrence of H2C-P. cells in rats and probably also in mice has not been substantially changed in animals exposed to factors interfering with chromatin structure and/or its template activity; the H2C-P. cells seem to be slightly more frequent after injecting mice with corticoids (Urbason) or in animals suffering from ectromelia or hereditary Purkinje cell degeneration. The incidence of H2C-P. cells has neither been substantially affected by experimental conditions which are known to lead to functional and/or metabolic stimulation of the cerebellum. Functional changes in the number of H2C-P. cell nuclei may, however, be short-term or transient in character and therefore might have excaped detection in our models. The findings rule out an impact of some reasons suspected for the artefactual origin of Feulgen H2C DNA values as e.g. compactness of the chromatin.