Ionotropic P2X receptors (P2XRs) are involved in sympathetic control of the vascular tone; they mediate entry of Ca2+ in smooth muscle cells (SMCs), which results in depolarization of the latter and activation of voltage-gated L-type calcium channels. In addition, Ca2+ ions, after their entry into the cell, trigger Ca2+ release from the sarcoplasmic reticulum (SR) of SMCs via ryanodine receptors (RyRs), and this amplifies calcium signals. We found earlier that Ca2+ release mediated by inositol triphosphate (IP3) receptors (IP3Rs) also provides a considerable contribution to P2XR-mediated calcium signaling. Thus, a metabotropic signal pathway is a component of the calcium signaling system triggered by ionotropic P2XRs. Using confocal detection of changes in the intracellular Ca2+ concentration ([Ca2+] i ) and applications of the inhibitors of calcium channels (nicardipine, 5 μM), sarco-endoplasmic Ca2+ ATPase SERCA (CPA, 10 μM), IP3Rs (2-APB, 30 μM), RyRs (tetracaine, 100 μM), and phosphalipase C (PLC; U-73122, 2.5 μM), we estimated relative contributions of the above-mentioned four components to increase in the [Ca2+] i induced by the action of an agonist of P2XRs, α,β-meATP. The contributions of transmembrane Ca2+ entry via channels of P2XRs and calcium channels were comparable (11.0 ± 1.4 %, n = 14 and 8.0 ± 1.4 %, n = 14, respectively). The contribution of Ca2+ release via IP3Rs was found to be three times greater than that via RyRs (41 ± 5 %, n = 26 and 14 ± 7 %, n = 16, respectively). Blocking of calcium channels resulted in a sevenfold decrease in the contribution of IP3R-mediated Ca2+ release (from 41.0 to 5.6%); in this case, the contribution of RyR-mediated Ca2+ release underwent no significant changes. This fact allows us to suppose that there is a functional relation between activation of calcium channels and functioning of a metabotropic PLC/IP3-mediated signal cascade. The efficiency of inhibition of α,β-meATP-induced calcium responses by the blocker of PLC, on the one hand, and by the IP3R blocker and nicardipine, on the other hand, is comparable, and this fact agrees with the above hypothesis. According to our data, P2XR activation-induced increase in [Ca2+] I results not only from P2XR-mediated Ca2+ entry that triggers Ca2+ release via RyRs but also from Ca2+ release via IP3Rs. The latter process is realized due to the functioning of the PLC-mediated pathway, is in close relation with activation of calcium channels, and provides a dominant contribution in Ca2+ release from the stores after activation of the above ionotropic receptors.
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References
D. L. Kreulen, “Properties of the venous and arterial innervations in the mesentery,” J. Smooth Muscle Res., 39, 269-279 (2003).
G. Burnstock and V. Ralevic, “New insights into the local regulation of blood flow by perivascular nerves and endothelium,” Br. J. Plast. Surg., 47, 527-543 (1994).
W. Zang, J. Zacharia, C. G. Lamont, et al., “Sympathetically evoked Ca2+ signaling in arterial smooth muscle,” Acta Pharmacol. Sin., 27, 1515-1525 (2006).
T. M. Egan, D. S. Samways, and Z. Li, “Biophysics of P2X receptors,” Pflügers Arch., 452, 501-512 (2006).
B. S. Khakh, G. Burnstock, C. Kennedy, et al., “International Union of Pharmacology. XXIV. Current status of the nomenclature and properties of P2X receptors and their subunits,” Pharmacol. Rev., 53, 107-118 (2001).
R. A. North, “Molecular physiology of P2X receptors,” Physiol. Rev., 82, No. 4, 1013-1067 (2002).
D. V. Gordienko, A. V. Zholos, and T. B. Bolton, “Membrane ion channels as physiological targets for local Ca2+ signaling,” J. Microsc., 196, No. 3, 305-316 (1999).
Z. Peng, A. Dang, and W. J. Arendshorst, “Increased expression and activity of phospholipase C in renal arterioles of young spontaneously hypertensive rats,” Am. J. Hypertens., 20, 38-43 (2007).
M. Iino, “Calcium-induced calcium release mechanism in guinea pig taenia caeci,” J. Gen. Physiol., 94, No. 2, 363-383 (1989).
Kh. Yu. Sukhanova, V. A. Buryj, V. F. Sagach, et al., “Effect of modulators of calcium metabolism on contraction of the guinea pig mesenterial artery upon activation of P2X receptors,” Fiziol. Zh., 55, No. 4, 74-82 (2009).
K. Starke, I. von Kügelgen, B. Driessen, et al., “ATP release and its prejunctional modulation,” Ciba Found. Symp., 198, 239-249 (1996).
D. Purves, G. J. Augustine, D. Fitzpatrick, et al., Neuroscience, Sinauer Associates. Inc., Sunderland, Massachusetts (2004).
R. J. Evans and A. Surprenant, “Vasoconstriction of guinea-pig submucosal arterioles following sympathetic nerve stimulation is mediated by the release of ATP,” Br. J. Pharmacol., 106, No. 2, 242-249 (1992).
G. Burnstock, “Physiology and pathophysiology of purinergic neurotransmission,” Physiol. Rev., 87, No. 2, 659-797 (2007).
O. V. Povstyan, M. I. Harhun, and D. V. Gordienko, “Ca2+ entry following P2X receptor activation induces IP3 receptor mediated Ca2+ release in renal resistance artery myocytes,” Br. J. Pharmacol., 162, 1618-1638 (2011).
C. J. Lewis and R. J. Evans, “Comparison of P2X receptors in rat mesenteric, basilar and septal (coronary) arteries,” J. Auton. Nerv. Syst., 81, Nos. 1/3, 69-74 (2000).
M. Suzuki, K. Muraki, Y. Imaizumi, et al., “Cyclopiazonic acid, an inhibitor of the sarcoplasmic reticulum Ca2+-pump, reduces Ca2+-dependent K+ currents in guinea-pig smooth muscle cells,” Br. J. Pharmacol., 107, 134-140 (1992).
V. Garaliene, V. Barsys, P. Jakuška, et al., “Action of calcium antagonists and agonists on isolated human thoracic arteries used for coronary artery bypass grafting,” Pharmacol. Res., 64, 733-738 (2012).
A. Del Valle-Rodrıguez, J. Lopez-Barneo, and J. Urena, “Ca2+ channel–sarcoplasmic reticulum coupling: a mechanism of arterial myocyte contraction without Ca2+ influx,” EMBO J., 22, 4337-4345 (2003).
T. Maruyama, T. Kanaji, S. Nakade, et al., “2-APB, 2-aminoethoxydiphenyl borate, a membrane-penetrable modulator of Ins(1,4,5)P3-induced Ca2+ release,” J. Biochem., 122, 498-505 (1997).
J. Urena, A. Del Valle-Rodrıguez, and J. Lopez-Barneo, “Metabotropic Ca2+ channel-induced calcium release in vascular smooth muscle,” Cell Calcium, 42, 513-520 (2007).
R. J. Smith, L. M. Sam, J. M. Justen, et al., “Receptor-coupled signal transduction in human polymorphonuclear neutrophils: effects of a novel inhibitor of phospholipase C-dependent processes on cell responsiveness,” J. Pharmacol. Exp. Ther., 253, 688-697 (1990).
D. Poburko, N. Fameli, K. H. Kuo, et al., “Ca2+ signaling in smooth muscle: TRPC6, NCX and LNats in nanodomains,” Channels, 2, No. 1, 10-12 (2008).
L. A. Blatter and W. G Weir, “Agonist-induced [Ca2+ ] i waves and Ca2+ -induced Ca2+ release in mammalian vascular smooth muscle cells,” Am. J. Physiol., 263, 576-586 (1992).
F. X. Boittin, N. Macrez, G. Halet, et al., “Norepinephrine-induced Ca2+ waves depend on InsP3 and ryanodine receptor activation in vascular myocytes,” Am. J. Physiol., 277, 139-151 (1999).
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Sukhanova, K.Y., Bouryi, V.A. & Gordienko, D.V. Convergence of Ionotropic and Metabotropic Signal Pathways upon Activation of P2X Receptors in Vascular Smooth Muscle Cells. Neurophysiology 46, 398–404 (2014). https://doi.org/10.1007/s11062-015-9464-7
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DOI: https://doi.org/10.1007/s11062-015-9464-7