DOI: https://doi.org/10.22263/2312-4156.2016.2.34
Lazuko S.S.
The role of the inducible NO-synthase in the regulation mechanisms of the functional activity of the ВКCа-channels in the coronary vessels of rats adapted to stress
Educational Establishment «Vitebsk State Order of Peoples’ Friendship Medical University», Vitebsk, Republic of Belarus
Vestnik VGMU. 2016;15(2):34-43.
Abstract.
To investigate the influence of the inducible NO-synthase (iNOS) on the functional activity of potassium ion channels activated by calcium with high conduction (ВКСа-channels) in the smooth muscle cells of the coronary vessels of rats in the process of the formation of adaptation to stress.
Experiments were carried out on 134 female white mongrel rats weighing 200-250 g. Adaptation to stress was reproduced by upright immobilization of rats in the plastic box filled with water (t=23±2°C) up to the level of the neck during 8 days. Coronary vessels’ tone and myocardial contractility were investigated on isolated by Langendorff’s method rats’ hearts perfused at the constant coronary flow (10 ml/min) with the standard composition of Krebs-Henseleight solution. The blockade of iNOS was realized with S-methylisothiourea (S-MT, 10-6 M). Tetraethylammonium (TEA), a blocker of ВКСа-channels, was added to the perfusion solution (1 mM) to evaluate the role of these channels in the regulation of the coronary blood flow and myocardial contractility. The contribution of ВКСа-channels to the regulation of coronary vessels’ tone was assessed by TEA-mediated vasoconstriction effect, i.e. the increment of the coronary perfusion pressure. The concentration of iNOS, endothelial NO-synthase (eNOS) and stable products of NO degradation (NO2-/NO3-) were detected with immuno-enzyme assay and spectrophotometric methods, accordingly.
It has been established that the addition of S-MT to the perfusion solution doesn’t lead to any changes of the coronary vessels’ tone and myocardial contractility both in the control group and in the group of the «adapted to stress». Animals coronary constrictor effect of TEA in the adapted animals was expressed to the same extend as in the control group. A simultaneous blockade of ВКСа-channels and iNOS results in the increase of coronary perfusion pressure by in the group of adapted animals 30% compared with the control data under the same conditions. A typical for the adaptation elevation of NO2-/NO3- concentration was accompanied by a decrease of iNOS and an increase of eNOS concentration.
Conclusions. The adaptation to stress leads to the functional activation of the ВКСа-channels, which reveals itself only after the blockade of iNOS, thus demonstrating strong dependence of their activity on the iNOS-derived nitric oxide.
Key words: ВКСа-channels, adaptation, inducible NO-synthase.
References
1. Wang X, Yin C, Xi L, Kukreja RC. Opening of Ca2+-activated K+ channels triggers early and delayed preconditioning against I/R injury independent of NOS in mice. Am J Physiol Heart Circ Physiol. 2004 Nov;287(5):H2070-7.
2. Ledoux J, Werner ME, Brayden JE, Nelson MT. Calcium-activated potassium channels and the regulation of vascular tone. Physiology. 2006 Feb;21:69-78.
3. Ko EA, Han J, Jung ID, Park WS. Physiological roles of K+ channels in vascular smooth muscle cells. J Smooth Muscle Res. 2008 Apr;44(2):65-81.
4. Gollasch M, Tank J, Luft FC, Jordan J, Maass P, Krasko C, Sharma AM, Busjahn A, Bähring S. The BK channel beta1 subunit gene is associated with human baroreflex and blood pressure regulation. J Hypertens. 2002 May;20(5):927-33.
5. Troncoso Brindeiro CM, Fallet RW, Lane PH, Carmines PK. Potassium channel contributions to afferent arteriolar tone in normal and diabetic rat kidney. Am J Physiol Renal Physiol. 2008 Jul;295(1):F171-8.
6. Clapp LH, Orie NN. Stoking up BKCa channels in hemorrhagic shock: which channel subunit is really fueling the fire? Circ Res. 2007 Aug;101(5):436-8.
7. Kyle BD, Braun AP. The regulation of BK channel activity by pre- and post-translational modifications. Front Physiol. 2014 Aug;5:316.
8. Gadek-Michalska A, Tadeusz J, Rachwalska P, Bugajski J. Chronic stress adaptiation of the nitric oxide synthases and IL-1G levels in brain structures and hypothalamic-pituitary-adrenal axis activity induced by homotypic stress. J Physiol Pharmacol. 2015 Jun;66(3):427-40.
9. Malenyuk EB, Aymasheva NP, Manukhina EB, Mikoyan VD, Kubrina LN, Vanin AF, Larionov NP, Malyshev IYu. Vovlechen li oksid azota v adaptatsionnuiu zashchitu organov ot stressornykh povrezhdenii? [Whether nitrogen oxide is involved in adaptic protection of organs from the stressornykh of damages?]. Biul Eksperiment Biologii i Meditsiny. 1998;126(9):274-7.
10. Veremey IS, Solodkov AP, Deyun GV, Golman VI. Vosstanovlenie NO2-/NO3- tsinkovoi pyl'iu v prisutstvii ammiachnogo kompleksa sul'fata medi [ Restoration of NO2-/NO3-zinc dust in the presence of an ammoniacal complex of copper sulfate]. V: 40 let farmatsevticheskomu fakul'tetu: sb nauch tr. Vitebsk, RB; 1999. Р. 274-6.
11. Abu-Saleh N, Ovcharenko E, Awad H, Goltsman I, Khamaisi M, Hoffman A, Heyman SN, Winaver J, Abassi Z. Involvement of the endothelin and nitric oxide systems in the pathogenesis of renal ischemic damage in an experimental diabetic model. Life Sci. 2012 Oct;91(13-14):669-75.
12. Kietadisorn R, Juni RP, Moens AL. Tackling endothelial dysfunction by modulating NOS uncoupling: new insights into its pathogenesis and therapeutic possibilities. Am J Physiol Endocrinol Metab. 2012 Mar;302(5):E481-95.
13. Manukhina EB, Belkina LM, Terekhina OL, Abramochkin DV, Smirnova EA, Budanova OP, Mallet RT, Downey HF. Normobaric, intermittent hypoxia conditioning is cardio- and vasoprotective in rats. Exp Biol Med. 2013 Dec;238(12):1413-20.
14. Meerson FZ, Pavlova VI, Sukhikh GT. Poststressornaia aktivatsiia sinteza nukleinovykh kislot i belkov i ee rol' v adaptatsionnykh reaktsiiakh organizma [Poststressic activation of synthesis of nucleic acids and proteins and its role in adaptic reactions of an organism]. Patol Fiziol i Eksperim Terapiia. 1982;(5):3-17.
15. Manukhina EB, Smirin BV, Malyshev IYu, Stoclet J-C, Muller B, Solodkov AP, Shebeko VI, Vanin AF. Deponirovanie oksida azota v serdechno-sosudistoi sisteme [Deposition of nitrogen oxide in cardiovascular system]. Izv RAN Ser Biol. 2002;(5):585-96.
16. Malyshev IYu, Malugin AV, Golubeva LYu, Zenina TA, Manukhina EB, Mikoyan VD, Vanin AF. Nitric oxide donor induces HSP70 accumulation in the heart and in cultured cells. FEBS Lett. 1996 Aug;391(1-2):21-3.
17. Pandit L, Kolodziejska KE, Zeng S, Eissa NT. The physiologic aggresome mediates cellular inactivation of iNOS. Proc Natl Acad Sci U S A. 2009 Jan;106(4):1211-5.
18. Wang T, Xia Y. Inducible nitric oxide synthase aggresome formation is mediated by nitric oxide. Biochem Biophys Res Commun. 2012 Sep;426(3):386-9.
