CARDIOVASCULAR SYSTEM AND INTERMITTENT STRESS: BLOODLESS ADAPTATION TO BLOOD LOSS Yurij V. Arkhipenko. Institute of General Pathology and Pathophysiology, Moscow, Russia.

An attempt has been made to use adaptation to stress for protection against the damaging action of acute blood loss. The experiments were carried out on male Wistar rats. Adaptation to stress was performed during 12 days by 1 h immobilization a day. After termination of the adaptation course, haemorrhagic shock was simulated in narcotized animals using catheterization of the femoral artery and multiple bleeding for 1 hour at arterial pressure of 40 mm Hg. Adaptation to intermittent stress induced specific changes in the hemodynamic parameters, the gas transport function, the acid-base state of the blood as well as the parameters of lipid peroxidation and the antioxidant status of different organs. They reflect enhanced resistance of stress- adapted rats to hypoxia. The data obtained suggest that haemorrhagic shock in adapted animals induces less pronounced changes in the tissue levels of 0, uptake in comparison with non-adapted ones. Adaptation increases the activities of endogenous antioxidants and the resistance to lipid peroxidation. Preliminary adaptation increases the lifetime in animals with haemorrhagic shock due to enhanced protection of the circulatory bed and the vital organs. All this makes adaptation to stress a promising and efficient procedure for increasing the resistance of the organism to bleeding and hemorrhagic shock. Supported by RFBR grant No 01-04-48252.

CARDIOMYOCYTE PROTEOME 2-D GEL DATABASE CONSTRUClIOl’k DETIWXION AND IDENTIFICATION OF CO-MIGRATING PROTEINS D. Kant hell’, Itine N-l, and Joaaifer E. Veo Eyk.jJ Dapt of Physiolog$ and Biocbemtstry’, Quam’s University, Kingston, ON, Canada

A vital component of the suceusful applicetion of protwmics tc cardiovMoldar lt#dr& is the CatabltsImlaelt of wq?hensivc p&inde&bwes,otlenvi4lyhthefonnof2Dgek,esrewt pr~oaic shldtas malt4 llae of this plueitl #pemtion techirple. Whilcidenti5caticaandlccalizationofa~witbins2Dgclir rdatively s@ai&&mrd for aber&at proteins or protcim p~~ly~arithinarpe*ap,3uehisnottbecaacEcrlow abumiamxproteiarorpmkiuiammycardiacmimalmerab mod& (i.e. dog, mbbit, wine) ht are w in hnt~ databsec. Applieeticm of “‘IN Squena”, e rapid sequenW nobhuhoeth m&cd, facilimtrd r&b& vcnnioular myocy%? pm& detection, Initial enrichmat of protein soluble af pbpiological pli leducul overall promome compIuity to rotghly 800 da&dabIa spots within a 2D gd, enban+ dctcctioo. of INKsrous low ebunhce p&eior not resohed plithin whole cell homogenates. Subsequent pracio idenfZceti0cl by peptido m.w hgaprihg (F%F) 0ftrypXic peptide 6qpnents isolated follow@ in-go1 dig&h and mess spawomeby rcvcelod that individuel proteius wsfc ofta nd lily feaolved within this subpfoteome atter 2D gel cl~hoteeis. Newtholess, co-migrsting pxueins were able to be i&t&d by mmipulatioa of PMF se+& pmmc%~~ when co- mlglldogprotsinrcach~dcdauoiguosubaatofmau6agm4nts. In this way it was possibte TV idanti@, for cxm&, both CK (43.1 kD, pl 6.63) awl scputate ahotmhsase (46.2, 6.68) from the same podion in a ZD gel+ as well as both SOD (22.7. 6.94) snd a proteolytic fragment of PAK-5 (80.8,8.19), a@ ffom a sit@4 spots

ISCHEMIC LOSS OF SARCOLEMMAL DYSTROPHIN AND SPECTRIN: CORRELATION WITH MYOCARDIAL INJURY Stephen Armstrong, Christine Shivell, Carole Latham and Charles Ganote. Dept of Pathology, East Tenn St. Univ, Johnson City, TN, 37614, USA

Sarcolemmai blebbing and rupture are prominent features of irreversible ischemic myocardial injury. Dystrophin and spectrin are sarcolemmal proteins. Dystrophin links the dystroglycan complex to F- actin. Spectrin forms the membrane skeleton, Loss of these proteins was detected by immuno- fluorescence in ischemic rabbit cardiomyocytes or LAD-ligated hearts. Western blots of microsomes and membrane fractions from ischemic myocytes showed a rapid loss (50% at 45 min) of dystrophin, which correlated with bleb formation, after hypotonic challenge. Loss of spectrin (50% at 180 min), from purified sarcolemma of autolysed rabbit heart, or microsomes and membrane fractions of ischemic cardiomyocytes, correlated with the degree of osmotic fragility. Preconditioning did not significantly alter these events. The dystrophin complex proteins, a sarcoglycan and p- dystroglycan, and an integral membrane protein (NaCa exchanger), were maintained in microsomes and the membrane fractions of ischemic cells. Loss of dystrophin and spectrin may contribute to bleb formation and membrane fragility during the transition to irreversible ischemic myocardial injury.

APSA AND CONTRACTILE FUNCTION OF GUINEA PIG HEART MUSCLE Laila Arvola, Diaa Hassaf & Kirsti Ytrehus. Kirkenes hospital and University of Tromss, Norway

Introduction: Diadenosine pentaphosphate (AP5A) has been reported to increase intracellular Ca2+ in some tissues by action on either P2-purinergic receptors or the P4-dinucleotide receptor, In the present study the effect of APsA upon contractility was studied in the guinea pig papillary muscle preparation, Methods: Preparations were paced at 1 Hz; 3 5°C. Adenosine deaminase was added to exclude the interaction with adenosine Al - receptors. The protocol contained 55 min stabilisation, 5 min test exposure and 45 min washout with Isoprotere- no1 (50nM) challenge at the end. Four groups were studied: I. Control. II. APsA (5OuM) during exposure, III. The P2-purinergic receptor antagonist Suramin (Sur) (1 OOpM) added through the last 2 minutes of stabilisa- tion and through exposure together with AP5A. IV. The P4-purinergic receptor antagonist diinosine pentaphos- phate (IP51) (301.&I) added as in group III. Results: Change after exposure to APsA was; APvl: ZIG., APd+Sur: 33+8, APJ+IPJ: 5*3 %. Change after exposure to isoproterenol was; Control: 56*15, APA: 19*7, APJA+SW: 20*6, APd+IPsI: 12*6 %. Results are mean f SEM. Conclusion: APsA exerts positive inotropic and sustained anti-8-adrenergic effect, the former but not the latter via P4-purinoceptors.

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