Assessment of the β2 adrenoceptor and Ca2+ channel-blocking activity of drugs with the rat portal vein

Journal of pharmacological methods Pub Date : 1990-09-01 DOI:10.1016/0160-5402(90)90025-G

Sheila A. Doggrell

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引用次数: 8

Abstract

The rat portal vein has spontaneous mechanical activity. The effects of β-adrenoceptor agonists and antagonists and verapamil alone and together on this mechanical activity have been determined. Isoprenaline, but not dobutamine, attenuated the contractile activity. Three successive challenges to isoprenaline produced identical attenuation curves. The responses to isoprenaline were antagonized by propranolol, metoprolol, and ICI 118,551, and the pA₂ values, derived by Schild analysis, were 9.12, 6.78, and 9.33, respectively. Thus, the rat portal vein contains predominantly β₂-adrenoceptors. Verapamil attenuated the contractile activity of the rat portal vein, and this attenuation was not altered by the presence of propranolol at 10⁻⁵ M. The potencies of isoprenaline and propranolol were not altered by the presence of a 30% attentuation of the contractile activity with verapamil at 10⁻⁷ M. Thus, the rat portal vein may be used to determine the potencies of drugs as β₂-adrenoceptor antagonists and as voltage dependent calcium channel blockers. In addition, the potency of drugs as β₂-adrenoceptor antagonists on the rat portal vein may be determined in the presence of some voltage dependent calcium channel blockade.

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大鼠门静脉内β2肾上腺素受体和Ca2+通道阻断活性的研究

大鼠门静脉有自发的机械活动。已经确定了β-肾上腺素能受体激动剂和拮抗剂以及维拉帕米单独和联合使用对这种机械活性的影响。异丙肾上腺素，而不是多巴酚丁胺，减弱了收缩活性。三次对异丙肾上腺素的连续挑战产生了相同的衰减曲线。异丙肾上腺素的反应被心得安、美托洛尔和ICI 118,551所拮抗，pA2值分别为9.12、6.78和9.33。因此，大鼠门静脉主要含有β2-肾上腺素受体。异丙肾上腺素和心得安在10−7 m时的收缩活性减弱30%，但它们的效力并没有被改变。因此，大鼠门静脉可以用来测定药物作为β2-肾上腺素受体拮抗剂和电压依赖性钙通道阻滞剂的效力。此外，β2-肾上腺素能受体拮抗剂对大鼠门静脉的效力可能是在存在电压依赖性钙通道阻断的情况下确定的。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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Journal of pharmacological methods

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