ABSTRACT
Lithium inhibits inositol monophosphatase at therapeutically effective concentrations, and it has been hypothesized that depletion of brain inositol levels is an important chemical alteration for lithium's therapeutic efficacy in bipolar disorder. We have employed adult rat cortical slices as a model to investigate the gene regulatory consequences of inositol depletion effected by lithium using cytidine diphosphoryl-diacylglycerol as a functionally relevant biochemical marker to define treatment conditions. Genes coding for the neuropeptide hormone pituitary adenylate cyclase activating polypeptide (PACAP) and the enzyme that processes PACAP's precursor to the mature form, peptidylglycine alpha-amidating monooxygenase, were upregulated by inositol depletion. Previous work has shown that PACAP can increase tyrosine hydroxylase (TH) activity and dopamine release, and we found that the gene for GTP cyclohydrolase, which effectively regulates TH through synthesis of tetrahydrobiopterin, was also upregulated by inositol depletion. We propose that modulation of brain PACAP signaling might represent a new opportunity in the treatment of bipolar disorder.
Subject(s)
Antimanic Agents/pharmacology , Biopterins/analogs & derivatives , Cerebral Cortex/drug effects , Cerebral Cortex/metabolism , Gene Expression Regulation/drug effects , Inositol/metabolism , Lithium Chloride/pharmacology , Animals , Biomarkers/metabolism , Biopterins/metabolism , Bipolar Disorder/metabolism , Cerebral Cortex/physiopathology , Cytidine Diphosphate Diglycerides/metabolism , Down-Regulation/drug effects , Down-Regulation/physiology , GTP Cyclohydrolase/genetics , GTP Cyclohydrolase/metabolism , Gene Expression Profiling , Gene Expression Regulation/physiology , Male , Mixed Function Oxygenases/metabolism , Multienzyme Complexes/metabolism , Nerve Growth Factors/biosynthesis , Neuropeptides/biosynthesis , Neurotransmitter Agents/biosynthesis , Oligonucleotide Array Sequence Analysis , Organ Culture Techniques , Pituitary Adenylate Cyclase-Activating Polypeptide , Rats , Rats, Sprague-Dawley , Tyrosine 3-Monooxygenase/biosynthesis , Up-Regulation/geneticsABSTRACT
Microarrays offer a high-resolution means for monitoring pre-mRNA splicing on a genomic scale. We have developed a novel, unbiased amplification protocol that permits labeling of entire transcripts. Also, hybridization conditions, probe characteristics, and analysis algorithms were optimized for detection of exons, exon-intron edges, and exon junctions. These optimized protocols can be used to detect small variations and isoform mixtures, map the tissue specificity of known human alternative isoforms, and provide a robust, scalable platform for high-throughput discovery of alternative splicing.
