2002 Fiscal Year Final Research Report Summary
Perivascular Sympathetic Nerve-Mediated Vasodilation in The Rat Mesenteric Resistance Artery
| Project/Area Number |
13672389
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
応用薬理学・医療系薬学
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
KAWASAKI Hiromu Okayama University Graduate School of Natural Science and Technology, Professor, 大学院・自然科学研究科, 教授 (60125151)
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| Co-Investigator(Kenkyū-buntansha) |
KUROSAKI Yuuji Okayama University Faculty of Pharmacuitical Sciences Professor, 薬学部, 教授 (90161786)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Sympathetic adrenergic nerves / Calcitonin gene-related peptide (CGRP)-nerves / Nicotine / Vanilloid receptors / Adrenergic neurotransmitters / Proton / Rat mesenteric resistance artery / 神経伝達物質 |
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| Research Abstract |
Nicotine has been shown to, in the rat mesenteric artery, cause a concentration-dependent and endothelium-independent vasodilator response, which is mediated by capsaicin-sensitive nerves and is associated with the intact adrenergic nerves. In the present study, mechanisms underlying the nicotine-induced vasodilation where further investigated in mesenteric resistance blood vessels of the Wistar rat. Isolated mesenteric vascular beds without endothelium were perfused with Krebs solution and contracted by 2-5 μM methoxamine and perfusion pressure was measured with a pressure transducer.
Perfusion of nicotine (1 to 100 μM) for 1 min caused a concentration-dependent vasodilation. The nicotine-induced vasodilation was inhibited by the vanilloid receptor antagonists, capsazepine(1 to 10 μM) and ruthenium red (1 to 30 μM), but did not by DOPA receptor antagonist (L-DOPA CHE), dopamine D1 and D2 receptor antagonist (SCH 23390 and haloperidol), ATP P2X receptor desensitizing agent (α, β-methylene ATP), neuropeptide Y1 receptor antagonist (BIBP3226), and adenosine A2 receptor antagonist (8-SPT). Catecholamine metabolites including normetanephrine and 3-methoxytyramine but not homovanillic acid induced concentration dependent-vasodilation, which was not inhibited by capsaicin treatment. The proton pump inhibitor, omeprazol, inhibited the nicotine-induced vasodilation in a concentration-dependent manner. These results suggest that vanilloid receptors on CGRPergic nerves may be activated by proton released by nicotine to cause vasodilation in the mesenteric resistance artery of the rat.
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