title: Ischemia enhances activation by Ca2+ and redox modification of ryanodine receptor channels from rat brain cortex.
abstract: Cerebral ischemia stimulates Ca2+ influx and thus increases neuronal intracellular free [Ca2+]. Using a rat model of cerebral ischemia without recirculation, we tested whether ischemia enhances the activation by Ca2+ of ryanodine receptor (RyR) channels, a requisite feature of RyR-mediated Ca2+-induced Ca2+ release (CICR). To this aim, we evaluated how single RyR channels from endoplasmic reticulum vesicles, fused into planar lipid bilayers, responded to cytoplasmic [Ca2+] changes. Endoplasmic reticulum vesicles were isolated from the cortex of rat brains incubated without blood flow for 5 min at 37 degrees C (ischemic) or at 4 degrees C (control). Ischemic brains displayed increased oxidative intracellular conditions, as evidenced by a lower ratio (approximately 130:1) of reduced/oxidized glutathione than controls (approximately 200:1). Single RyR channels from ischemic or control brains displayed the same three responses to Ca2+ reported previously, characterized by low, moderate, or high maximal activity. Relative to controls, RyR channels from ischemic brains displayed with increased frequency the high activity response and with lower frequency the low activity response. Both control and ischemic cortical vesicles contained the RyR2 and RyR3 isoforms in a 3:1 proportion, with undetectable amounts of RyR1. Ischemia reduced [3H]ryanodine binding and total RyR protein content by 35%, and increased at least twofold endogenous RyR2 S-nitrosylation and S-glutathionylation without affecting the corresponding RyR3 endogenous levels. In vitro RyR S-glutathionylation but not S-nitrosylation favored the emergence of high activity channels. We propose that ischemia, by enhancing RyR2 S-glutathionylation, allows RyR2 to sustain CICR; the resulting amplification of Ca2+ entry signals may contribute to cortical neuronal death.
authors.affiliation: Centro de Estudios Moleculares de la Célula, Fondo de Investigación Avanzada en Areas Prioritarias, Universidad de Chile, Santiago 7, Chile. rbull@med.uchile.cl
authors.forename: Ricardo
authors.initials: R
authors.lastname: Bull
authors.forename: José Pablo
authors.initials: JP
authors.lastname: Finkelstein
authors.forename: Jorge
authors.initials: J
authors.lastname: Gálvez
authors.forename: Gina
authors.initials: G
authors.lastname: Sánchez
authors.forename: Paulina
authors.initials: P
authors.lastname: Donoso
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Behrens
authors.forename: Cecilia
authors.initials: C
authors.lastname: Hidalgo
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D002545:Brain Ischemia / Q000378:metabolism* / Q000503:physiopathology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D016923:Cell Death / Q000502:physiology; D002540:Cerebral Cortex / Q000378:metabolism* / Q000503:physiopathology; D003593:Cytoplasm / Q000378:metabolism; D004195:Disease Models, Animal; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D008297:Male; D009410:Nerve Degeneration / Q000378:metabolism* / Q000503:physiopathology; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D013347:Subcellular Fractions; D022161:Transport Vesicles / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology
chemical_list: D019837:Ryanodine Receptor Calcium Release Channel; D005978:Glutathione; D002118:Calcium
references.citation: Mol Pharmacol. 1994 Feb;45(2):189-200
references.pmid: 8114670
references.citation: Prog Neurobiol. 2000 Dec;62(6):649-71
references.pmid: 10880854
references.citation: Nature. 1998 Oct 15;395(6703):645-8
references.pmid: 9790183
references.citation: J Cell Biol. 1995 Mar;128(5):893-904
references.pmid: 7876312
references.citation: J Biol Chem. 1998 Jun 26;273(26):16011-20
references.pmid: 9632651
references.citation: Cell Mol Neurobiol. 1999 Feb;19(1):119-31
references.pmid: 10079971
references.citation: Antioxid Redox Signal. 2005 Jul-Aug;7(7-8):870-81
references.pmid: 15998242
references.citation: Neurosci Lett. 1993 Aug 6;158(1):105-8
references.pmid: 8233063
references.citation: J Biol Chem. 2003 Oct 31;278(44):42927-35
references.pmid: 12920114
references.citation: J Mol Cell Cardiol. 2005 Dec;39(6):982-91
references.pmid: 16242147
references.citation: J Neurosci. 1994 Aug;14(8):4794-805
references.pmid: 8046450
references.citation: Stroke. 2005 Feb;36(2):189-92
references.pmid: 15637315
references.citation: Nat Rev Mol Cell Biol. 2002 Mar;3(3):214-20
references.pmid: 11994742
references.citation: J Neurosci. 2008 Sep 17;28(38):9463-72
references.pmid: 18799678
references.citation: Pflugers Arch. 2004 May;448(2):131-8
references.pmid: 14770314
references.citation: J Biol Chem. 1996 Mar 1;271(9):5079-84
references.pmid: 8617786
references.citation: J Biol Chem. 2006 Dec 29;281(52):40354-68
references.pmid: 17071618
references.citation: Biophys J. 2000 Jul;79(1):279-86
references.pmid: 10866954
references.citation: J Neurosci Res. 2005 Oct 15;82(2):196-205
references.pmid: 16175570
references.citation: Stroke. 2007 Feb;38(2 Suppl):674-6
references.pmid: 17261713
references.citation: Cell Calcium. 2007 May;41(5):491-502
references.pmid: 17074386
references.citation: FEBS Lett. 1996 Mar 25;383(1-2):59-62
references.pmid: 8612791
references.citation: Mech Ageing Dev. 2004 Apr;125(4):325-35
references.pmid: 15063109
references.citation: Biophys J. 1989 Oct;56(4):749-56
references.pmid: 2554991
references.citation: Cell. 2000 Aug 18;102(4):499-509
references.pmid: 10966111
references.citation: Brain Res. 2005 Jun 28;1048(1-2):59-68
references.pmid: 15921666
references.citation: J Mol Cell Cardiol. 2003 Dec;35(12):1429-37
references.pmid: 14654369
references.citation: Am J Physiol Cell Physiol. 2003 Jul;285(1):C119-28
references.pmid: 12637263
references.citation: Eur J Pharmacol. 2002 Jul 5;447(2-3):189-200
references.pmid: 12151011
references.citation: Front Biosci. 2002 May 01;7:a72-9
references.pmid: 11991848
references.citation: J Neurochem. 1996 Dec;67(6):2390-8
references.pmid: 8931471
references.citation: J Neurochem. 1991 Mar;56(3):1075-8
references.pmid: 1671584
references.citation: Physiol Rev. 2005 Jan;85(1):201-79
references.pmid: 15618481
references.citation: Neuron. 1999 Jan;22(1):115-24
references.pmid: 10027294
references.citation: J Biol Chem. 1993 Jul 15;268(20):15111-7
references.pmid: 8325886
references.citation: Am J Physiol Cell Physiol. 2007 Jul;293(1):C162-71
references.pmid: 17360812
references.citation: J Neurosci Res. 2005 Mar 15;79(6):816-24
references.pmid: 15668910
references.citation: J Proteome Res. 2007 Jul;6(7):2822-32
references.pmid: 17536849
references.citation: J Biol Chem. 2000 Nov 24;275(47):36556-61
references.pmid: 10952995
references.citation: Antioxid Redox Signal. 2008 Sep;10(9):1549-64
references.pmid: 18479206
references.citation: Neurosci Lett. 1997 Jan 31;222(2):91-4
references.pmid: 9111736
references.citation: Biol Res. 2002;35(2):183-93
references.pmid: 12415735
references.citation: J Neurophysiol. 2004 Nov;92(5):2960-7
references.pmid: 15201305
references.citation: Front Biosci. 2007 Jan 01;12:1376-86
references.pmid: 17127388
references.citation: Anesthesiology. 2002 Mar;96(3):705-10
references.pmid: 11873048
references.citation: Cell Calcium. 2004 Sep-Oct;36(3-4):313-22
references.pmid: 15261487
references.citation: Anal Biochem. 1980 Jul 15;106(1):207-12
references.pmid: 7416462
references.citation: J Neurochem. 2004 Oct;91(2):327-36
references.pmid: 15447666
references.citation: J Cell Mol Med. 2003 Oct-Dec;7(4):351-61
references.pmid: 14754504
references.citation: J Pharmacol Exp Ther. 2001 May;297(2):474-8
references.pmid: 11303032
references.citation: Neuron. 2003 Sep 25;40(1):53-63
references.pmid: 14527433
references.citation: Biophys J. 1998 Mar;74(3):1263-77
references.pmid: 9512024
references.citation: Resuscitation. 2001 Jul;50(1):117-25
references.pmid: 11719138
references.citation: Biochem Biophys Res Commun. 1998 Apr 17;245(2):428-9
references.pmid: 9571168
references.citation: Antioxid Redox Signal. 2005 Sep-Oct;7(9-10):1150-7
references.pmid: 16115018
references.citation: Biophys J. 2003 Apr;84(4):2319-30
references.pmid: 12668440
references.citation: Free Radic Biol Med. 2006 Feb 1;40(3):388-97
references.pmid: 16443153
references.citation: Brain Res Dev Brain Res. 2003 Dec 30;147(1-2):77-84
references.pmid: 14741753