This should make it easier to detect the effects of specific genetic variants. Intermediate phenotypes referable to hippocampus have received attention because of its role in neuropsychiatrie disorders such as schizophrenia. Promising intermediate phenotypes have included measures of episodic memory, hippocampal activation

assayed with functional magnetic resonace imaging (fMRI), and hippocampal volume assayed with MRI, among others. In addition to these Inhibitors,research,lifescience,medical relatively complex intermediate phenotypes, each gene also has related phenotypic measures based on its function. For example, the dopamine D2 receptor exerts its effects by modulating intracellular cyclic adenosine monophosphate (cAMP) levels and therefore one can study the functional effects of mutations in the D2 gene by examining downstream effects on cAMP levels. Thus, Inhibitors,research,lifescience,medical the impact of a specific genetic variant in a gene Inhibitors,research,lifescience,medical can be studied at basic cellular level, as well as at the systems level. BDNF is an obvious candidate gene for hippocampal function in humans because studies in animals have shown BDNF to be a critical mediator of episodic

memory. For example, BDNF plays an essential role in the Inhibitors,research,lifescience,medical molecular mechanisms of both early and late phases of long-term potentiation (LTP) through both

presynaptic and postsynaptic mechanisms. To exert these effects, BDNF is packaged and transported to dendrites, where it is released and acts as a retrograde messenger. Despite this work in nonhumans, it has been unclear what role BDNF played in the greatly expanded, verbally mediated episodic Inhibitors,research,lifescience,medical memory in humans. The BDNF gene is 66.8 kilobases, has 9 exons, and produces at least 6 splice variants. All 5′ exons are spliced out and only the final 3′ exon is translated into protein. Translation produces a precursor protein, which is packaged into secretory vesicles and eventually cleaved at amino over acid 128 to form the mature BDNF protein. The BDNF gene was recently found to contain at least one common polymorphism that changes amino acid sequence. This is the val66met polymorphism at codon 66, which creates a valine to methionine substitution in the preprotein. Other missense single nucleotide polymorphisms (SNPs) have been described, but appear to be uncommon. Because val66met is only in the preprotein, it has no effect on the structure or in vitro activity of the mature BDNF protein. The relevance of this polymorphism for humans was first Selleck Androgen Receptor Antagonist examined in a study of intermediate phenotypes related to schizophrenia.