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首页> 外文期刊>Clinical and experimental pharmacology & physiology >Mechanisms of alpha,beta-methylene atp-induced inhibition in rat ileal smooth muscle: involvement of intracellular Ca2+ stores in purinergic inhibition.
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Mechanisms of alpha,beta-methylene atp-induced inhibition in rat ileal smooth muscle: involvement of intracellular Ca2+ stores in purinergic inhibition.

机译：大鼠回肠平滑肌中α，β-亚甲基atp诱导的抑制机制：细胞内Ca2 +存储参与嘌呤能抑制。

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1. In order to investigate purinergic effects on rat ileal smooth muscle, we used alpha,beta-methylene ATP (alpha,beta-MeATP), ATP, ADP and UTP. alpha,beta-Methylene ATP and ATP were the only agonists that caused a concentration-dependent inhibition of carbachol-precontracted smooth muscle. The inhibitory effect of alpha,beta-MeATP was completely blocked by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (3 x 10(-5) mol/L), a selective antagonist of the P2X > > P2Y receptor. 2. Using reverse transcription-polymerase chain reaction we demonstrated the presence of both, P2X and P2Y receptor mRNA within the rat ileal longitudinal muscle/myenteric plexus layer preparation. 3. The alpha,beta-MeATP-induced inhibition was blocked in a concentration-dependent manner in the presence of the K+ channel blocker apamin, but was unaffected by other K+ channel blockers, such as charybdotoxin (10(-7) mol/L), 4-aminopyridine (10(-4)mol/L), glibenclamide (10(-5) mol/L) and tetraethylammonium (10(-3) mol/L). 4. The alpha,beta-MeATP-induced inhibition was unaffected by pretreatment with atropine (10(-6) mol/L), phentolamine (10(-6) mol/L), propranolol (10(-6) mol/L), nitrendipine (10(-7) mol/L), pertussis toxin (10(-6) mol/L) NG-nitro-L-arginine (3 x 10(-4) mol/L) and tetrodotoxin (10(-6) mol/L), excluding an involvement of adrenergic, cholinergic, neural, nitrinergic or G-protein involvement in purinergic-mediated inhibition. 5. In order to investigate whether the internal Ca2+ stores participated in the inhibitory effect observed, we depleted internal Ca2+ stores with cyclopiazonic acid, a specific Ca2+-ATPase inhibitor. The inhibitory effect of alpha,beta-MeATP was completely abolished after depletion of the intracellular Ca2+ stores. 6. This is in contrast with the effects seen for neurotensin, where neurotensin-induced inhibition was unchanged after depletion of intracellular Ca2+ stores, suggesting at least two different pathways of apamin-sensitive non-adrenergic, non-cholinergic inhibition in rat ileal smooth muscle. 7. According to our results, the inhibitory effect of alpha,beta-MeATP in rat ileum longitudinal smooth muscle is mediated via a P2 purinoceptor, most likely a P2X receptor, involves G-protein-independent activation of an apamin-sensitive K+ channel and requires filled intracellular Ca+ stores.
机译：1.为了研究嘌呤对大鼠回肠平滑肌的作用，我们使用了α，β-亚甲基ATP（alpha，β-MeATP），ATP，ADP和UTP。 α，β-亚甲基ATP和ATP是引起浓度依赖性抑制卡巴胆碱收缩的平滑肌的唯一激动剂。吡ido醛磷酸盐-6-偶氮苯基-2'，4'-二磺酸（3 x 10（-5）mol / L）（P2X P2Y受体的选择性拮抗剂）完全阻断了α，β-MeATP的抑制作用。 2.使用逆转录-聚合酶链反应，我们证明了在大鼠回肠纵向肌肉/肌层神经丛层制备物中同时存在P2X和P2Y受体mRNA。 3.在K +通道阻滞剂apamin存在下，α，β-MeATP诱导的抑制作用以浓度依赖性方式被阻断，但不受其他K +通道阻滞剂的影响，例如charybdotoxin（10（-7）mol / L ），4-氨基吡啶（10（-4）mol / L），格列本脲（10（-5）mol / L）和四乙铵（10（-3）mol / L）。 4.用阿托品（10（-6）mol / L），酚妥拉明（10（-6）mol / L），普萘洛尔（10（-6）mol / L）预处理不影响α，β-MeATP诱导的抑制作用），尼群地平（10（-7）mol / L），百日咳毒素（10（-6）mol / L）NG-硝基-L-精氨酸（3 x 10（-4）mol / L）和河豚毒素（10（ -6）mol / L），不包括肾上腺素能，胆碱能，神经，亚硝酸能或G蛋白参与嘌呤能介导的抑制作用。 5.为了研究内部Ca2 +存储库是否参与了所观察到的抑制作用，我们用一种特定的Ca2 + -ATPase抑制剂环吡唑酸来耗尽内部Ca2 +存储库。细胞内Ca2 +储存耗尽后，α，β-MeATP的抑制作用被完全消除。 6.这与神经降压素的作用相反，后者在细胞内Ca2 +储存耗尽后，神经降压素诱导的抑制作用没有改变，提示对大鼠回肠平滑肌的至少20种不同途径的谷氨酰胺敏感性非肾上腺素，非胆碱能抑制。 7.根据我们的结果，α，β-MeATP在大鼠回肠纵向平滑肌中的抑制作用是通过P2嘌呤受体（最可能是P2X受体）介导的，涉及到G蛋白非依赖性的对蛋白蛋白敏感的K +通道的激活和需要填充细胞内Ca +存储区。

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