Boonen H C, De Mey J G
Department of Pharmacology, University of Limburg, Maastricht, The Netherlands.
Eur J Pharmacol. 1990 Apr 25;179(3):403-12. doi: 10.1016/0014-2999(90)90181-5.
We recorded the contractile responses to calcium in mesenteric resistance arteries of Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) during depolarization or stimulation with noradrenaline. The effects of Bay-K8644 and nimodipine on these responses were evaluated. Calcium sensitivity was greater in noradrenaline-stimulated than in depolarized vessels. Nimodipine decreased and Bay-K8644 increased calcium sensitivity. Both substances were more potent in the presence of potassium than in the presence of noradrenaline. Calcium sensitivity was greater in SHR than in WKY vessels only during stimulation with noradrenaline. The rhythmic responses of SHR vessels during stimulation with noradrenaline were abolished by nimodipine. Rhythmicity could be induced in WKY vessels by Bay-K8644. Modulation of calcium sensitivity by dihydropyridines during electrochemical as well as pharmacological stimulation suggests that, in resistance arterial smooth muscle, the function of potential-operated calcium channels can be modulated by noradrenaline. This modulation could differ quantitatively between mesenteric resistance arteries of SHR and WKY.
我们记录了在去极化或用去甲肾上腺素刺激期间，Wistar Kyoto（WKY）大鼠和自发性高血压大鼠（SHR）肠系膜阻力动脉对钙的收缩反应。评估了Bay-K8644和尼莫地平对这些反应的影响。去甲肾上腺素刺激的血管中钙敏感性高于去极化血管。尼莫地平降低而Bay-K8644增加钙敏感性。两种物质在钾存在下比在去甲肾上腺素存在下更有效。仅在去甲肾上腺素刺激期间，SHR血管中的钙敏感性高于WKY血管。尼莫地平消除了SHR血管在去甲肾上腺素刺激期间的节律性反应。Bay-K8644可在WKY血管中诱导出节律性。在电化学以及药理学刺激期间二氢吡啶对钙敏感性的调节表明，在阻力动脉平滑肌中，电压门控性钙通道的功能可被去甲肾上腺素调节。这种调节在SHR和WKY的肠系膜阻力动脉之间可能在数量上有所不同。
