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.
MeSH terms
-
Animals
-
Antimanic Agents / pharmacology*
-
Biomarkers / metabolism
-
Biopterins / analogs & derivatives*
-
Biopterins / metabolism
-
Bipolar Disorder / metabolism
-
Cerebral Cortex / drug effects*
-
Cerebral Cortex / 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 / drug effects*
-
Gene Expression Regulation / physiology
-
Inositol / metabolism*
-
Lithium Chloride / pharmacology*
-
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 / genetics
Substances
-
Adcyap1 protein, rat
-
Antimanic Agents
-
Biomarkers
-
Cytidine Diphosphate Diglycerides
-
Multienzyme Complexes
-
Nerve Growth Factors
-
Neuropeptides
-
Neurotransmitter Agents
-
Pituitary Adenylate Cyclase-Activating Polypeptide
-
Biopterins
-
Inositol
-
Mixed Function Oxygenases
-
Tyrosine 3-Monooxygenase
-
peptidylglycine monooxygenase
-
GTP Cyclohydrolase
-
sapropterin
-
Lithium Chloride