Publication de 4 numéros par an
ISSN Imprimer: 2155-014X
ISSN En ligne: 2155-0158
Contribution of Ca2+ Entry and Ca2+ Release Mechanisms to Purinergic Contraction of the Guinea-Pig Small Mesenteric Arteries
RÉSUMÉ
ATP evokes changes in the vascular tone through activation of P2X and P2Y purinoceptors. To evaluate relative contribution of Ca2+ entry through voltage-gated calcium channels and Ca2+-release from the sarcoplasmic reticulum (SR) to contraction of vascular smooth muscles induced by P2X receptor activation, we tested the effects of antagonists of IP3 receptors, IP3Rs, (60 μM of 2-APB) and ryanodine receptors, RyRs, (100 μM of tetracaine) on isometric tension of endothelium-denuded mesenteric artery rings stimulated with P2X receptor agonist α,β-meATP (10 μM) before and following block of the L-type voltage-gated calcium channels (VGCCs) with nicardipine (5 μM). We have found that inhibition of either RyRs or IP3Rs or VGCCs attenuated α,β-meATP – induced phasic contractile responses. Interestingly, the contractile response to α,β-meATP in the presence of nicardipine was found to be less sensitive to inhibition of IP3Rs than RyRs ((47.1 ± 9.5) % and (22.9 ± 1.4) % comparing to (38.3 ± 9.6) % and (51.8 ± 7.8) % in control solution for IP3R and RyR inhibition, respectively). This finding suggests that Ca2+ entry through VGCCs is primarily linked to activation of IP3Rs rather than RyRs. This suggestion is further supported by immunolocalization of IP3Rs and RyRs. Confocal imaging revealed that subplasmalemmal SR elements are enriched with IP3Rs, while RyRs are predominantly located in the central perinuclear SR elements.
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Sukhanova Khrystyna Yu., Thugorka Oleksandr M., Bouryi Vitali A., Harhun Maksym I., Gordienko Dmitri V., Mechanisms of the sarcoplasmic reticulum Ca2+ release induced by P2X receptor activation in mesenteric artery myocytes, Pharmacological Reports, 66, 3, 2014. Crossref
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Sukhanova Khrystyna Yu., Harhun Maksym I., Bouryi Vitali A., Gordienko Dmitri V., Mechanisms of [Ca2+]i elevation following P2X receptor activation in the guinea-pig small mesenteric artery myocytes, Pharmacological Reports, 65, 1, 2013. Crossref