Holmquist F, Andersson K E, Hedlund H
Department of Clinical Pharmacology, University Hospital, Lund, Sweden.
Acta Physiol Scand. 1990 Apr;138(4):463-9. doi: 10.1111/j.1748-1716.1990.tb08873.x.
Intracavernous injection of vasoactive agents causing vasodilatation is widely recognized in the diagnosis and treatment of erectile dysfunction. However, papaverine, the drug most commonly used for this purpose, may produce priapism and fibrotic lesions, and alternatives without these disadvantages are desirable. In this study we investigated the effects of pinacidil, a vasodilator drug supposed to act through the opening of K+ channels, on isolated human corpus cavernosum penis. Besides abolishing spontaneous contractile activity, pinacidil effectively relaxed preparations precontracted by noradrenaline 10(-6) M and inhibited contractions induced by electrical field stimulation of nerves. Furthermore, pinacidil depressed contractions induced by low-K+ solutions (less than or equal to 20 mM) and concentration-dependently increased the efflux of 86Rb from preloaded tissue. The results suggest that pinacidil is effective in relaxing isolated human erectile tissue, probably by way of increased K+ permeability and subsequent hyperpolarization. Clinical testing seems justified in order to find out if K(+)-channel openers can be used in the pharmacological treatment of impotence.
海绵体内注射引起血管舒张的血管活性药物在勃起功能障碍的诊断和治疗中已得到广泛认可。然而，用于此目的最常用的药物罂粟碱可能会导致阴茎异常勃起和纤维化病变，因此需要没有这些缺点的替代药物。在本研究中，我们研究了吡那地尔（一种据推测通过开放钾通道起作用的血管舒张药物）对离体人阴茎海绵体的影响。除了消除自发收缩活性外，吡那地尔还能有效松弛由10(-6)M去甲肾上腺素预收缩的标本，并抑制电场刺激神经诱导的收缩。此外，吡那地尔可抑制低钾溶液（小于或等于20mM）诱导的收缩，并浓度依赖性地增加预加载组织中86Rb的外流。结果表明，吡那地尔可能通过增加钾通透性和随后的超极化有效地松弛离体人勃起组织。为了确定钾通道开放剂是否可用于阳痿的药物治疗，进行临床试验似乎是合理的。
