Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Brain levels of tyrosine, dopamine (DA), noradrenaline (NA), tryptophan, 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were measured after 30, 60 and 120 min of sustained seizure activity, induced in paralyzed, artificially ventilated and anaesthetized (70% N2O) rats by administration of bicuculline (1.2 mg/kg i.v.). In separate animals the rates of accumulation of DOPA and 5-hydroxytryptophan (5-HTP) were estimated in three different brain regions after blockage of the aromatic L-amino acid decarboxylase with NSD 1015 (100 mg/kg). The tissue level of NA was markedly reduced at 30 min and remained low during 120 min of sustained epileptic seizures. In contrast, the DA concentration, being essentially unaffected at 30 min, continuously increased during the following 90 min. 5-HT decreased significantly after 30 min but returned to control levels following 60 and 120 min of seizure activity. The 5-HIAA concentration progressively increased. In all three brain regions (striatum, limbic forebrain and hemispheres) the rate of tyrosine hydroxylation increased. Tryptophan hydroxylation showed a significant increase only in the limbic forebrain. The results suggest that bicuculline-induced seizures lead to an increased functional activity in NA neurons and, at least initially, also in 5-HT neurons. In contrast, DA neurons appear to be inhibited.
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PMID:Monoamine metabolism during bicuculline-induced epileptic seizures in the rat. 30 80

In the mouse, neurotransmitter metabolism can be regulated by modulation of the synthesis of pyridoxal 5'-phosphate and failure to maintain pyridoxal phosphate (PLP) levels results in epilepsy. This study of five patients with neonatal epileptic encephalopathy suggests that the same is true in man. Cerebrospinal fluid and urine analyses indicated reduced activity of aromatic L-amino acid decarboxylase and other PLP-dependent enzymes. Seizures ceased with the administration of PLP, having been resistant to treatment with pyridoxine, suggesting a defect of pyridox(am)ine 5'-phosphate oxidase (PNPO). Sequencing of the PNPO gene identified homozygous missense, splice site and stop codon mutations. Expression studies in Chinese hamster ovary cells showed that the splice site (IVS3-1g>a) and stop codon (X262Q) mutations were null activity mutations and that the missense mutation (R229W) markedly reduced pyridox(am)ine phosphate oxidase activity. Maintenance of optimal PLP levels in the brain may be important in many neurological disorders in which neurotransmitter metabolism is disturbed (either as a primary or as a secondary phenomenon).
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PMID:Neonatal epileptic encephalopathy caused by mutations in the PNPO gene encoding pyridox(am)ine 5'-phosphate oxidase. 1577 97