title: [Role of the inositol phosphate cycle in the cardioprotective effect of adaptation to intermittent hypoxia].
abstract: The impact of adaptation to intermittent hypoxia of different duration (for 20 and 40 days) on the inositol triphosphate-diacylglycerol (ITP-DAG) regulatory contour in the heart was investigated. For this, isolated heart alpha 1-adrenoreactivity to phenylephrine and phospholipase (PhL-C) activities were studied in cardiac plasma membranes. On day 20 of adaptation, the heart inotropic response to phenylephrine stimulation was somewhat reduced and the activity of Ca(2+)-dependent PhL-C did not differ from that in the controls within the range of Ca2+ physiological concentrations. Forty days after adaptation, both positive inotropic responses of the heart to phenylephrine and activity of Ca(2+)-dependent PhL-C were enhanced, i.e. activation of the ITP-DAG regulatory cascade occurred. Early studies have shown that a phenomenon of adaptive stabilization develops at this stage of adaptation. The phenomenon appears as a significant increase in heart resistance to thermal injury, toxic catecholamine levels, Ca2+ paradox and high Ca2+ concentrations. Thus, the revealed activation of the ITP-DAG regulatory contour was accompanied by the development of a phenomenon of adaptive structure stabilization (PhASS) in the hearts of adapted animals. The findings suggest that the ITP-DAG regulatory cascade plays an important role in the cardioprotective effect of adaptation to intermittent hypobaric hypoxia and in PhASS formation.
authors.forename: Iu N
authors.initials: IuN
authors.lastname: Kopylov
authors.forename: F Z
authors.initials: FZ
authors.lastname: Meerson
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D015687:Cell Hypoxia / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000502:physiology*; D008297:Male; D009206:Myocardium / Q000166:cytology; D010507:Periodicity; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007295:Inositol Phosphates
vernacular_title: Rol' inozitolfosfatnogo tsikla v kardioprotektornom éffekte adaptatsii k periodicheskoĭ gipoksii.