title: Oroxylin A increases BDNF production by activation of MAPK-CREB pathway in rat primary cortical neuronal culture.
abstract: Oroxylin A (5,7-dihydroxy-6-methoxyfavone) is a flavonoid compound originated from the root of Scutellaria baicalensis Georgi. Our previous reports suggested that oroxylin A improves memory function in rat, at least in part, by its antagonistic effects on GABA(A) receptor. In addition, oroxylin A protects neurons from ischemic damage by mechanisms currently not clear. In this study we determined whether oroxylin A modulates the level of brain derived neurotrophic factor (BDNF) in primary rat cortical neuronal culture, which is well known for its role on neuronal survival, neurogenesis, differentiation of neurons and synapses and learning and memory. Treatment of oroxylin A for 3-48h increased BDNF expression which was analyzed by ELISA assay and Western blot analysis. Oroxylin A induced slow but sustained increases in intracellular calcium level and activated ERK1/2 mitogen activated protein kinase (MAPK). In addition, oroxylin A phosphorylated cyclic AMP response element binding protein (CREB) at Ser 133 in concentration and time dependent manner. Pretreatment with the MAPK inhibitor PD98059 (10μM) attenuated phosphorylation of ERK1/2 and CREB as well as BDNF production, which suggests that oroxylin A regulates BDNF production by activating MAPK-CREB pathway. GABA(A) antagonist bicuculline mimicked the effects of oroxylin A on BDNF production as well as MAPK-CREB pathway. Increase in intracellular Ca(2+) concentration, phosphorylation of ERK1/2 and CREB, and BDNF expression by oroxylin A was blocked by NMDA receptor inhibitor MK-801 (10μM) as well as tetrodotoxin (TTX, 0.5 and 1μM). The results from the present study suggest that the calcium and p-CREB dependent induction of BDNF expression, possibly via activation of synaptic NMDA receptor through the blockade of GABA(A) activity in cortical neuronal circuitry, might be responsible for the neuroprotective or memory enhancing effects of oroxylin A.
authors.affiliation: Department of Pharmacology, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, San 56-1, Shillim-Dong, Kwanak-Gu, Seoul 151-742, Republic of Korea.
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Jeon
authors.forename: So Young
authors.initials: SY
authors.lastname: Rhee
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Seo
authors.forename: Hae Rang
authors.initials: HR
authors.lastname: Bak
authors.forename: Sung Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Ryu
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Cheong
authors.forename: Chan Young
authors.initials: CY
authors.lastname: Shin
authors.forename: Gun-Hee
authors.initials: GH
authors.lastname: Kim
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Lee
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Ko
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D050882:CREB-Binding Protein / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004622:Embryo, Mammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology*; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D009118:Muscimol / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D005419:Flavonoids; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D012333:RNA, Messenger; D026941:Sodium Channel Blockers; D009118:Muscimol; D013779:Tetrodotoxin; C080669:5,7-dihydroxy-6-methoxy-2-phenylchromen-4-one; D016291:Dizocilpine Maleate; D050882:CREB-Binding Protein; D020929:Mitogen-Activated Protein Kinase Kinases; D002118:Calcium; D001640:Bicuculline