Vascular smooth muscle cells from small human omental arteries express P2X1 and P2X4 receptor subunits.

ABSTRACT: Stimulation of P2X receptors by ATP in vascular smooth muscle cells (VSMCs) is proposed to mediate vascular tone. However, understanding of P2X receptor-mediated actions in human blood vessels is limited, and therefore, the current work investigates the role of P2X receptors in freshly isolated small human gastro-omental arteries (HGOAs). Expression of P2X1 and P2X4 receptor subunit messenger RNA (mRNA) and protein was identified in individual HGOA VSMCs using RT-PCR and immunofluorescent analysis and using Western blot in multi-cellular preparations. ATP of 10 ?mol/l and ??-meATP of 10 ?mol/l, a selective P2X receptor agonist, evoked robust increases in [Ca(2+)]i in fluo-3-loaded HGOA VSMCs. Pre-incubation with 1 ?mol/l NF279, a selective P2X receptor antagonist, reduced the amplitude of ??-meATP-induced increase in [Ca(2+)]i by about 70 %. ATP of 10 ?mol/l and ??-meATP of 10 ?mol/l produced similar contractile responses in segments of HGOA, and these contractions were greatly reduced by 2 ?mol/l NF449, a selective P2X receptor inhibitor. These data suggest that VSMCs from HGOA express P2X1 and P2X4 receptor subunits with homomeric P2X1 receptors likely serving as the predominant target for extracellular ATP.

SUBMITTER: Nichols CM 

PROVIDER: S-EPMC4272371 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature