Neuroleptics and Microglial Activation Associated with Neuropsychiatric Disorders - Abstract
Microglial activation is one of common pathological findings in the lesions of many neurodegenerative diseases. In the 1980’s immunohistochemical studies, using anti-major histocompatibility complex class II (MHCII) antibodies identified activated microglia in postmortem brains of neurodegenerative diseases. Microglial activation in the brains of patients with neurodegenerative diseases has been demonstrated since 2000 by positron emission tomography studies employing PK11195. Moreover, activated microglia have also recently been implicated in endogenous psychiatric disorders, such as schizophrenia and mood disorders, where common pathological findings had never before been identified. However, the exact functional states of microglial activation in neuropsychiatric diseases remain to be clarified, since an increase in expression of a microglial marker MHC II or PK11195 is not necessarily an indicator of classical inflammatory microglial activation. Accumulating evidence shows that both antidepressants and antipsychotics attenuate the classical activation of microglia, suggesting that such an action may be associated with their therapeutic effects. It is clearly desirable to establish reliable markers that would identify specific microglial activation states in neuropsychiatric diseases.