title: Postsynaptic action of brain-derived neurotrophic factor attenuates alpha7 nicotinic acetylcholine receptor-mediated responses in hippocampal interneurons.
abstract: Nicotinic mechanisms acting on the hippocampus influence attention, learning, and memory and constitute a significant therapeutic target for many neurodegenerative, neurological, and psychiatric disorders. Here, we report that brain-derived neurotrophic factor (BDNF) (1-100 ng/ml), a member of the neurotrophin gene family, rapidly decreases alpha7 nicotinic acetylcholine receptor responses in interneurons of the hippocampal CA1 stratum radiatum. Such effect is dependent on the activation of the TrkB receptor and involves the actin cytoskeleton; noteworthy, it is compromised when the extracellular levels of the endogenous neuromodulator adenosine are reduced with adenosine deaminase (1 U/ml) or when adenosine A(2A) receptors are blocked with SCH 58261 (2-(2-furanyl)-7-(2-phenylethyl)-7H-pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine) (100 nm). The intracellular application of U73122 (1-[6[[(17beta)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione) (5 mum), a broad-spectrum inhibitor of phospholipase C, or GF 109203X (bisindolylmaleimide I) (2 mum), a general inhibitor of protein kinase C isoforms, blocks BDNF-induced inhibition of alpha7 nicotinic acetylcholine receptor function. Moreover, in conditions of simultaneous intracellular dialysis of the fast Ca(2+) chelator BAPTA (10 mm) and removal of extracellular Ca(2+) ions, the inhibitory action of BDNF is further prevented. The present findings disclose a novel target for rapid actions of BDNF that might play important roles on synaptic transmission and plasticity in the brain.
authors.affiliation: Institute of Pharmacology and Neurosciences, Faculty of Medicine and Unit of Neurosciences, Institute of Molecular Medicine, University of Lisbon, 1649-028 Lisbon, Portugal. cfernandes@fm.ul.pt
authors.forename: Catarina C
authors.initials: CC
authors.lastname: Fernandes
authors.forename: António
authors.initials: A
authors.lastname: Pinto-Duarte
authors.forename: Joaquim Alexandre
authors.initials: JA
authors.lastname: Ribeiro
authors.forename: Ana M
authors.initials: AM
authors.lastname: Sebastião
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology*; D002038:Bungarotoxins / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D004347:Drug Interactions; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D006624:Hippocampus / Q000166:cytology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000187:drug effects* / Q000502:physiology; D008297:Male; D018408:Patch-Clamp Techniques / Q000379:methods; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D051381:Rats; D011978:Receptors, Nicotinic / Q000502:physiology*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014230:Triazoles / Q000494:pharmacology; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: C098657:5-amino-7-(2-phenylethyl)-2-(2-furyl)pyrazolo(4,3-e)-1,2,4-triazolo(1,5-c)pyrimidine; D019208:Brain-Derived Neurotrophic Factor; D002038:Bungarotoxins; D002614:Chelating Agents; C579165:Chrna7 protein, rat; D018690:Excitatory Amino Acid Agonists; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D011978:Receptors, Nicotinic; D026941:Sodium Channel Blockers; D014230:Triazoles; D064569:alpha7 Nicotinic Acetylcholine Receptor; D013779:Tetrodotoxin; D004533:Egtazic Acid; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; C056639:2-amino-5-phosphopentanoic acid; D014633:Valine; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D000109:Acetylcholine