کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2533268 1559048 2010 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Interaction between α1- and α2-adrenoreceptors contributes to enhanced constrictor effects of norepinephrine in mesenteric veins compared to arteries
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب سلولی و مولکولی
پیش نمایش صفحه اول مقاله
Interaction between α1- and α2-adrenoreceptors contributes to enhanced constrictor effects of norepinephrine in mesenteric veins compared to arteries
چکیده انگلیسی

Mesenteric veins are more sensitive than arteries to the constrictor effects of sympathetic nerve stimulation and α-adrenoceptor agonists. We tested the hypothesis that α1- and α2-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 μM, α2-adrenoceptor receptor agonist) did not constrict arteries or veins but enhanced constrictions and Ca2+ signals mediated by α1-adrenoceptor stimulation in veins. Yohimbine (α2-adrenoceptor receptor antagonist) and MK912 (α2C-adrenoceptor receptor antagonist), but not α2A- or α2B-adrenoceptor antagonists, produced rightward shifts in norepinephrine concentration–response curves in veins. Pharmacological studies revealed that α1D-adrenoceptors mediate venous constrictions. Norepinephrine responses in veins from α2C-adrenoceptor knock-out (KO) mice were not different from wild type veins. Yohimbine inhibited norepinephrine constrictions in α2C-adrenoceptor KO veins suggesting that there is upregulation of other α2-adrenoceptors in α2C-KO mice. These data indicate that α1D- and α2C-adrenoceptors interact in veins but not in arteries. This interaction enhances venous adrenergic reactivity. Mesenteric vein-specific α2-adrenoceptor linked Ca2+ and perhaps other signaling pathways account for enhanced venous adrenergic reactivity.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: European Journal of Pharmacology - Volume 643, Issues 2–3, 25 September 2010, Pages 239–246
نویسندگان
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