title: [The role of ATP-dependent potassium channels and nitric oxide system in the neuroprotective effect of preconditioning].
abstract: OBJECTIVE
  To study a role of ATP-dependent potassium channels (K+ATP) in the neuroprotective effect of ischemic (IP) and pharmacological (PP) preconditioning and evaluate the dynamics of blood nitric oxide (NO) metabolites in cerebral ischemia.
  
  
  METHODS
  A model of ischemic stroke induced by the electrocoagulation of a middle cerebral artery (MCA) branch was used in male rats (n=86). Glibenclamide, a selective inhibitor of ATP-sensitive K+ channels, and diazoxide, a potassium channel activator, were used. IP and PP were performed 24 h before MCA occlusion. Blood concentrations of NO, NO3- and NO2-were measured 5, 24 and 72 h after occlusion.
  
  
  RESULTS
  IP decreased a lesion area by 37% (p<0/05) and the preliminary introduction ofglibenclamide levelled the effect of IP. A protective effect of PP was similar to that of IP. A decrease in oxygenated R-conformers of Hb-NO and a reverse increase in non-oxygenated T-conformers as well as NO3- и NO2-were noted 5h after MCA occlusion. In the first 24 h after MCA occlusion, contents of NO3- and NO2- returned to normal values. There were changes in the concentrations of Hb-NO complexes as well, with the predominance of R-conformers and minimal contents of T-conformers. Moreover, the correlations between K+ATP channel blockade and the decrease in serum NO3- and NO2 were found (p<0/03).
  
  
  CONCLUSIONS
  The neuroprotective effect of preconditioning is caused by the activation of K+ATP channels. An analysis of NO metabolite concentrations in the blood of rats with IP suggests that Hb-NO complexes belonging to R-conformers deposit and carry NO in tissues releasing NO accumulated via R→T transfer in conditions of ischemia.
authors.affiliation: Lomonosov Moscow State University, Moscow, Russia.
authors.forename: O G
authors.initials: OG
authors.lastname: Deryagin
authors.affiliation: Lomonosov Moscow State University, Moscow, Russia.
authors.forename: S A
authors.initials: SA
authors.lastname: Gavrilova
authors.affiliation: Lomonosov Moscow State University, Moscow, Russia.
authors.forename: S V
authors.initials: SV
authors.lastname: Buravkov
authors.affiliation: Kazan Physical-Technical Institute of Russian Academy of Sciences, Kazan, Russia; Institute of Fundamental Medicine and Biology of Kazan Federal University, Kazan, Russia.
authors.forename: V V
authors.initials: VV
authors.lastname: Andrianov
authors.affiliation: Institute of Fundamental Medicine and Biology of Kazan Federal University, Kazan, Russia.
authors.forename: G G
authors.initials: GG
authors.lastname: Yafarova
authors.affiliation: Kazan Physical-Technical Institute of Russian Academy of Sciences, Kazan, Russia; Institute of Fundamental Medicine and Biology of Kazan Federal University, Kazan, Russia.
authors.forename: Kh L
authors.initials: KL
authors.lastname: Gainutdinov
authors.affiliation: Lomonosov Moscow State University, Moscow, Russia.
authors.forename: V B
authors.initials: VB
authors.lastname: Koshelev
mesh_terms: D000255:Adenosine Triphosphate; D000818:Animals; D003981:Diazoxide; D005905:Glyburide; D020244:Infarction, Middle Cerebral Artery; D019157:Ischemic Preconditioning, Myocardial; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D015221:Potassium Channels / Q000502:physiology; D051381:Rats
chemical_list: D018696:Neuroprotective Agents; D015221:Potassium Channels; D009569:Nitric Oxide; D000255:Adenosine Triphosphate; D003981:Diazoxide; D005905:Glyburide