抵抗性冠動脈のベータ2アドレナジック膨張は,意識のある犬のKATPチャネルと酸化窒素を伴う
1Department of Physiology, Faculty of Medicine, Université de Montréal, Québec, Canada.
Circulation
|March 18, 1997
まとめ
ベータ2型アドレナジック刺激は,ATPに敏感なカリウム (KATP) 経路を開き,酸化窒素 (NO) の形成を誘発することで冠動脈を広げます. NOまたはKATPチャネルを遮断することで,犬におけるこの膨張が著しく減少しました.
科学分野:
- 心血管生理学 心血管生理学
- 薬理学 薬理学とは
背景:
- ベータ2アドレナジック刺激は,ATP感受性カリウム (KATP) 経路と酸化窒素 (NO) 形成を通じて冠動脈を広げると仮定されています.
- このメカニズムを理解することは,冠動脈の血流の管理に不可欠です.
研究 の 目的:
- ベータ2アドレナジック媒介による冠動脈血管拡張におけるKATPチャネルとNO形成の役割を調査する.
- 冠動脈の血流の調節におけるKATPチャネルとNOの相互作用を決定する.
主な方法:
- 意識のある計測された犬は,β1-アドレナージックブロックを受けた.
- アセチルコリン,ニトログリセリン,ピルブテロール (β2-アゴニスト) の冠内投与は,NO形成 (L-NAMEを使用) またはKATPチャネル (グリベンクラミドを使用) の阻害の前におよび後に実施されました.
- 冠動脈血流 (CBF) と遠冠動脈圧を測定した.
主要な成果:
- ピルブテロールによる冠動脈血流の増加は,L-NAMEとグリベンクラミドの両方によって有意に減少しました.
- アセチルコリン反応はL-NAMEによっても弱まり,ニトログリセリン反応はどちらかのブロックによっても影響を受けなかった.
- レマカリム (KATPチャネルオープナー) は,用量依存によりCBFを増加させ,L-NAME.によって部分的に抑制される効果である.
結論:
- 冠動脈抵抗性血管のベータ2アドレナージ的血管拡張は,KATPチャネル開口とNO形成の両方を含む.
- 犬の冠動脈のKATPチャネル開口とNO形成の間には,L-NAME対抗性レマカリム反応が示すように,機能的な関連がある.
関連する概念動画
Nitric Oxide Signaling Pathway
Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure to...
Adrenergic Receptors (Adrenoceptors): Classification
Adrenergic receptors, or adrenoceptors, respond to the autonomic neurotransmitter noradrenaline and other endogenous catecholamine agonists. They are classified into two main families, α and β, based on their pharmacological response and are further subdivided depending on their location, elicited response, and affinity to specific agonists or antagonists.
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
Adrenergic Receptors: β Subtype
β-adrenoceptors have varied sensitivities towards adrenaline, noradrenaline, and isoprenaline. The order of agonist potency is as follows:
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Adrenergic Agonists: Direct-Acting Agents
Drugs that mimic the action of endogenous catecholamines like noradrenaline and adrenaline are called adrenergic agonists or sympathomimetics. Based on their mechanism of action, sympathomimetics can be classified as direct-, indirect-, or mixed-acting sympathomimetics. Direct-acting adrenergic agonists activate adrenoceptors without affecting presynaptic neurons, making them independent of neuronal catecholamine-depleting agents like reserpine and guanethidine.
These agents can be classified...
These agents can be classified...
Antihypertensive Drugs: Vasodilators
Vasodilators, primarily affecting the smooth muscles within arterial and venous walls, are commonly used for hypertension treatment. Medications such as minoxidil and hydralazine primarily target arteries and arterioles, while sodium nitroprusside acts on arterioles and venules. Minoxidil, functioning as a prodrug, is metabolized by hepatic sulfotransferase into its active form, minoxidil sulfate, after oral administration. This metabolite binds to the sulfonylurea receptor (SUR) component of...
Antianginal Drugs: Nitrates and β-Blockers
In cardiovascular health, antianginal drugs combat angina pectoris — a condition marked by chest pain owing to diminished blood flow to the heart.
Organic nitrates, such as nitroglycerin, play a pivotal role. Once metabolized, they liberate nitric oxide, a molecular marvel. Nitric oxide triggers guanylyl cyclase and augments cGMP production. This biochemical cascade orchestrates the relaxation of vascular smooth muscles, ushering in vasodilation and enhancing coronary blood flow. Administered...
Organic nitrates, such as nitroglycerin, play a pivotal role. Once metabolized, they liberate nitric oxide, a molecular marvel. Nitric oxide triggers guanylyl cyclase and augments cGMP production. This biochemical cascade orchestrates the relaxation of vascular smooth muscles, ushering in vasodilation and enhancing coronary blood flow. Administered...


