The alpha7 nicotinic acetylcholine receptor in schizophrenia: decreased mRNA levels in peripheral blood lymphocytes

Abstract

Recent studies have suggested that the alpha7 nicotinic acetylcholine receptor (alpha7 AChR) may play a role in the pathogenesis of schizophrenia. In search for peripheral biological markers for schizophrenia we have investigated alpha7 mRNA levels in peripheral blood lymphocytes (PBLs) of schizophrenic patients and healthy controls. Peripheral blood samples were collected from medicated and non-medicated (drug naive) schizophrenic patients as well as from healthy (non-mentally ill) smokers and non-smokers. RNA was prepared from isolated lymphocytes. Polymerase chain reaction products specific for human alpha7 AChR were quantified by densitometry using Scion image-analysis (shared NIH software). We observed a significant decrease of alpha7 mRNA levels on PBLs of schizophrenic patients compared with controls. The decrease in alpha7 mRNA levels was not a result of medication management, because non-medicated schizophrenic patients displayed the same level of reduction in alpha7 mRNA as did patients receiving medication. In addition, we exclude the possibility that the observed decrease in alpha7 mRNA levels resulted from nicotine consumption in smoking, because healthy smokers exhibited the same levels of alpha7 mRNA as non-smokers. We propose that alpha7 AChR may be involved in the pathophysiology of the disease and may serve as a reliable peripheral biological marker in schizophrenia.