Changes in calcineurin expression induced in the rat brain by the administration of antipsychotics.

Calcineurin (CN) was recently identified as a susceptibility gene for schizophrenia as well as showing altered RNA expression levels in the post-mortem brains of individuals with schizophrenia. CN knockout mice show a number of behaviours associated with schizophrenia, including deficits in sensorimotor gating, suggesting a link between CN and psychosis. Concurrently, we found, using genome screening techniques, that antipsychotics alter CN expression levels. Therefore, western blotting, in situ hybridization, immunocytochemistry and phosphatase assays were employed to determine what effect antipsychotics have on CN. The results indicate that clozapine, risperidone and haloperidol cause substantial reductions in the A subunit of CN but not CN B at both the RNA and protein levels in the striatum and prefrontal cortex. The changes could only be observed after repeated treatment with antipsychotics but not after acute administration. The alterations in CN protein levels were specific to antipsychotics and mediated by D2 dopamine receptor antagonism. However, despite reductions in CN protein levels, the phosphatase activity of CN was significantly elevated after treatment with antipsychotics. Collectively the results suggest that CN may be a common target for antipsychotics and that antipsychotic-induced alterations in CN may represent one of the mechanisms by which antipsychotics alleviate psychosis.

Torus palatinus and torus mandibularis: a review of the literature.

The torus has been mentioned in the literature for about 180 years. However, little has been revealed about it until the last two decades when great advances were made in the field of genetics. Its occurrence in various ethnic groups ranges from 9 to 66 per cent. Even between similar ethnic groups living in different environments, different figures have been reported. It has been statistically proven that differences do occur between various ethnic groups and the sexes. In current thinking, the occurrence of tori is considered to be an interplay of genetic and environmental factors. The quasi-continuous genetic or threshold model seems to hold the answers to their formation. This theory proposes that the environmental factors responsible must first reach a threshold level before the genetic factors can express themselves in the individual. Hence, both genetic and environmental factors determine liability, making the system multifactorial.