title: ATP-dependent potassium channel blockade strengthens microglial neuroprotection after hypoxia-ischemia in rats.
abstract: Stroke causes CNS injury associated with strong fast microglial activation as part of the inflammatory response. In rat models of stroke, sulphonylurea receptor blockade with glibenclamide reduced cerebral edema and infarct volume. We postulated that glibenclamide administered during the early stages of stroke might foster neuroprotective microglial activity through ATP-sensitive potassium (K(ATP)) channel blockade. We found in vitro that BV2 cell line showed upregulated expression of K(ATP) channel subunits in response to pro-inflammatory signals and that glibenclamide increases the reactive morphology of microglia, phagocytic capacity and TNFα release. Moreover, glibenclamide administered to rats 6, 12 and 24h after transient Middle Cerebral Artery occlusion improved neurological outcome and preserved neurons in the lesioned core three days after reperfusion. Immunohistochemistry with specific markers to neuron, astroglia, microglia and lymphocytes showed that resident amoeboid microglia are the main cell population in that necrotic zone. These reactive microglial cells express SUR1, SUR2B and Kir6.2 proteins that assemble in functional K(ATP) channels. These findings provide that evidence for the key role of K(ATP) channels in the control of microglial reactivity are consistent with a microglial effect of glibenclamide into the ischemic brain and suggest a neuroprotective role of microglia in the early stages of stroke.
authors.affiliation: Unitat de Bioquímica i Biologia Molecular, Facultat de Medicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain.
authors.forename: F J
authors.initials: FJ
authors.lastname: Ortega
authors.forename: J
authors.initials: J
authors.lastname: Gimeno-Bayon
authors.forename: J F
authors.initials: JF
authors.lastname: Espinosa-Parrilla
authors.forename: J L
authors.initials: JL
authors.lastname: Carrasco
authors.forename: M
authors.initials: M
authors.lastname: Batlle
authors.forename: M
authors.initials: M
authors.lastname: Pugliese
authors.forename: N
authors.initials: N
authors.lastname: Mahy
authors.forename: M J
authors.initials: MJ
authors.lastname: Rodríguez
mesh_terms: D000818:Animals; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005905:Glyburide / Q000494:pharmacology / Q000627:therapeutic use*; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy* / Q000378:metabolism; D054086:KATP Channels / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008297:Male; D051379:Mice; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D026902:Potassium Channel Blockers / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000187:drug effects
chemical_list: D054086:KATP Channels; D018696:Neuroprotective Agents; D026902:Potassium Channel Blockers; D005905:Glyburide