title: Regulation of glycinergic and GABAergic synaptogenesis by brain-derived neurotrophic factor in developing spinal neurons.
abstract: Brain-derived neurotrophic factor (BDNF) effects on the establishment of glycinergic and GABAergic transmissions in mouse spinal neurons were examined using combined electrophysiological and calcium imaging techniques. BDNF (10 ng/ml) caused a significant acceleration in the onset of synaptogenesis without large effects on the survival of these neurons. Amplitude and frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) and miniature inhibitory postsynaptic currents (mIPSCs) associated to activation of glycine and GABA(A) receptors were augmented in neurons cultured with BDNF. The neurotrophin effect was blocked by long term tetrodotoxin (TTX) addition suggesting a dependence on neuronal activity. In addition, BDNF caused a significant increase in glycine- and GABA-evoked current densities that partly explains the increase in synaptic transmission. Presynaptic mechanisms were also involved in BDNF effects since triethylammonium(propyl)-4-(2-(4-dibutylamino-phenyl)vinyl)pyridinium (FM1-43) destaining with high K(+) was augmented in neurons incubated with the neurotrophin. The effects of BDNF were mediated by receptor tyrosine kinase B (TrkB) and mitogen-activated protein kinase kinase (MEK) activation since culturing neurons with either (9S,10R,12R)-2,3,9,10,11,12-hexahydro-10-hydroxy-9-methyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'- kl]pyrrolo[3,4-i][1,6]benzodiazocine-10-carboxylic acid methyl ester (K252a) or 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one (PD98059) blocked the augmentation in synaptic activity induced by the neurotrophin.
authors.affiliation: Laboratory of Neurophysiology, Department of Physiology, University of Concepción, P.O. Box 160-C, Concepción, Chile.
authors.forename: M A
authors.initials: MA
authors.lastname: Carrasco
authors.forename: P
authors.initials: P
authors.lastname: Castro
authors.forename: F J
authors.initials: FJ
authors.lastname: Sepulveda
authors.forename: J C
authors.initials: JC
authors.lastname: Tapia
authors.forename: K
authors.initials: K
authors.lastname: Gatica
authors.forename: M I
authors.initials: MI
authors.lastname: Davis
authors.forename: L G
authors.initials: LG
authors.lastname: Aguayo
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism* / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005998:Glycine / Q000378:metabolism*; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D020813:Receptor, trkB / Q000187:drug effects / Q000378:metabolism; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism; D018009:Receptors, Glycine / Q000187:drug effects / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000196:embryology; D013569:Synapses / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D004791:Enzyme Inhibitors; C073804:FM1 43; D011726:Pyridinium Compounds; D000644:Quaternary Ammonium Compounds; D011963:Receptors, GABA-A; D018009:Receptors, Glycine; D026941:Sodium Channel Blockers; D005680:gamma-Aminobutyric Acid; D020813:Receptor, trkB; D048369:MAP Kinase Kinase 1; C482127:Map2k1 protein, mouse; D005998:Glycine