Mesenteric veins are more sensitive than arteries to the constrictor effects of sympathetic nerve stimulation and alpha-adrenoceptor agonists. We tested the hypothesis that alpha(1)- and alpha(2)-adrenoceptors interact to enhance adrenergic reactivity of mesenteric veins. We studied neurogenic and agonist-induced constrictions of mesenteric veins and arteries in vitro. Norepinephrine concentration-response curves were left-shifted in veins compared to arteries. UK 14,304 (0.01-1 microM, alpha(2)-adrenoceptor receptor agonist) did not constrict arteries or veins but enhanced constrictions and Ca(2+) signals mediated by alpha(1)-adrenoceptor stimulation in veins. Yohimbine (alpha(2)-adrenoceptor receptor antagonist) and MK912 (alpha(2C)-adrenoceptor receptor antagonist), but not alpha(2A)- or alpha(2B)-adrenoceptor antagonists, produced rightward shifts in norepinephrine concentration-response curves in veins. Pharmacological studies revealed that alpha(1D)-adrenoceptors mediate venous constrictions. Norepinephrine responses in veins from alpha(2C)-adrenoceptor knock-out (KO) mice were not different from wild type veins. Yohimbine inhibited norepinephrine constrictions in alpha(2C)-adrenoceptor KO veins suggesting that there is upregulation of other alpha(2)-adrenoceptors in alpha(2C)-KO mice. These data indicate that alpha(1D)- and alpha(2C)-adrenoceptors interact in veins but not in arteries. This interaction enhances venous adrenergic reactivity. Mesenteric vein-specific alpha(2)-adrenoceptor linked Ca(2+) and perhaps other signaling pathways account for enhanced venous adrenergic reactivity.
- MeSH
- alfa-1-adrenergní receptory - agonisté farmakologie MeSH
- alfa-1-adrenergní receptory metabolismus fyziologie MeSH
- alfa-2-adrenergní receptory - agonisté farmakologie MeSH
- alfa-2-adrenergní receptory - antagonisté farmakologie MeSH
- alfa-2-adrenergní receptory genetika metabolismus fyziologie MeSH
- arteriae mesentericae účinky léků fyziologie MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- noradrenalin fyziologie MeSH
- protein - isoformy antagonisté a inhibitory MeSH
- sympatický nervový systém účinky léků MeSH
- vápníková signalizace účinky léků MeSH
- vazokonstrikce účinky léků MeSH
- vena mesenterica účinky léků fyziologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- srovnávací studie MeSH
- techniky in vitro MeSH
Microvessels respond to metabolic stimuli (e.g. pO(2)) and hemodynamic forces (e.g. shear stress and wall stress) with structural adaptations including angiogenesis, remodeling and pruning. These responses could be mediated by differential gene expression in endothelial and smooth muscle cells. Therefore, rat mesenteric arteries and veins were excised by microsurgery, and mRNA expression of four angioadaptation-related genes was quantified by real time duplex RT-PCR in equal amounts of total RNA, correlated to two different house keeping genes (beta-actin, GAPDH). The results show higher expression of VEGFA, TIE2, and ANG2 in arteries than in veins, but equal expression of ADAMTS1. Higher availability of VEGFA mRNA in endothelial cells of arteries shown here could contribute to the maintenance of mechanically stressed blood vessels and counteract pressure-induced vasoconstriction.
- MeSH
- angiopoetin-2 genetika MeSH
- arteriae mesentericae fyziologie MeSH
- cévní endotel fyziologie MeSH
- exprese genu fyziologie MeSH
- fyziologická adaptace fyziologie MeSH
- krysa rodu rattus MeSH
- messenger RNA metabolismus MeSH
- mikrocirkulace fyziologie MeSH
- polymerázová řetězová reakce s reverzní transkripcí MeSH
- potkani Sprague-Dawley MeSH
- proteiny ADAM genetika MeSH
- receptor TIE-2 genetika MeSH
- svaly hladké cévní fyziologie MeSH
- vaskulární endoteliální růstový faktor A genetika MeSH
- vazokonstrikce fyziologie MeSH
- vena mesenterica fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
