Yang X P, Chiba S
Department of Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan.
Heart Vessels. 1998;13(5):256-61. doi: 10.1007/BF03257249.
P2X-Purinoceptors and alpha1-adrenoceptors have previously been shown to be involved in double-peaked vasoconstrictor responses to periarterial electrical nerve stimulation in the isolated and perfused canine splenic artery. The present study was designed to investigate the influence of endothelium removal on vasoconstrictor responses to periarterial nerve stimulation, tyramine, noradrenaline, and adenosine triphosphate (ATP) in the isolated canine splenic artery. Intraluminal administration of saponin completely abolished the acetylcholine-induced vasodilatation and potentiated the vasoconstrictor response to KCl. Double-peaked vasoconstriction (two phases of vasoconstriction) was readily induced by periarterial electrical nerve stimulation in the canine splenic arterial preparation with or without endothelium and was consistently abolished by treatment with tetrodotoxin. Removal of endothelium slightly but significantly decreased the first-phase vasoconstrictor responses to stimulation of 1 or 10 Hz, and did not affect the second-phase. The vasoconstrictor responses to tyramine, noradrenaline, and ATP were not modified by endothelium removal. From these results, it is postulated that ATP released from endothelium, as a modulator of sympathetic nerve cotransmission, may partially contribute to the purinergic constriction component in the canine splenic artery.
P2X嘌呤受体和α1肾上腺素受体先前已被证明参与了在离体灌注犬脾动脉中对动脉周围电神经刺激的双峰血管收缩反应。本研究旨在探讨去除内皮对离体犬脾动脉中对动脉周围神经刺激、酪胺、去甲肾上腺素和三磷酸腺苷（ATP）的血管收缩反应的影响。腔内给予皂苷完全消除了乙酰胆碱诱导的血管舒张，并增强了对氯化钾的血管收缩反应。在有或没有内皮的犬脾动脉制备物中，动脉周围电神经刺激很容易诱导出双峰血管收缩（两个血管收缩阶段），并且用河豚毒素处理可始终消除这种反应。去除内皮略微但显著降低了对1或10Hz刺激的第一阶段血管收缩反应，并且不影响第二阶段。去除内皮对酪胺、去甲肾上腺素和ATP的血管收缩反应没有影响。从这些结果推测，作为交感神经共同传递调节剂的内皮释放的ATP可能部分促成犬脾动脉中的嘌呤能收缩成分。
