Expression of glutamatergic, serotoninergic and GABAergic receptors in the amygdala, hippocampus and prefrontal cortex of rats after acquisition and extinction of fear conditioning: potential therapeutic targets of the standardized extract of Ginkgo biloba

Abstract

Although it has been suggested that the standardized Gingko biloba leaf extract may have a benefic effect on memory, his efficacy as a nootropic agent has been questioned because it is unclear if the improvements observed are consequences of direct action of Ginkgo on memory processes or reflect an improvement in attention, vascular tissue, alertness, or even for acting in anxiety disorders and depression. Understanding the cellular and molecular mechanisms in neural structures involved in memory formation of conditioned fear is important to understand effects of EGb on central nervous system. The progress in understanding the biological basis is important for there to be therapeutic advances in prevention and treatment of diseases associated with memory disorders and anxiety. Several studies have suggested that the glutamatergic, gabaergic and serotonergic transmission are major strategic targets for treatment of anxiety disorders, and participate in memory formation of conditioned fear. Thus, this study intend to analyze the protein and gene expression to glutamatergic, serotoninergic and gabaergic receptors in the hippocampus, amygdaloid complex and prefrontal cortex of rats submitted for conditioned emotional response (REC) and acute, subacute and chronic treatment with Ginkgo Biloba Extract (EGb 761). The gene and protein expression of NMDA, GABAA and 5-HT1A be carried out by quantitative PCR (qPCR) and immunofluorescence double staining, respectively, in samples of hippocampus, amygdaloid complex and prefrontal cortex. Analysis of differentially expressed genes and proteins in astrocytes using antibodies against glial fibrillary acidic protein (GFAP) and neurons by analysis of neurofilament (anti-NF) will enable us to evaluate the interaction between the cell types in the learning process associated with the use of herbal medicines. Statistical analysis of gene expression will be performed to test one-way ANOVA followed by Scheffe test and the analysis of the number of cells U test Mann-Whitney. (AU)