Sen A P, Bhattacharya S K, Ramarao P
Department of Pharmaceutics, Banaras Hindu University, Varanasi, India.
Indian J Exp Biol. 1992 Feb;30(2):107-9.
Calcium channels were studied in isolated spontaneously rhythmic rabbit jejunum using the muscarinic agonist carbachol as stimulant. Carbachol failed to produce the characteristic phasic and tonic components of smooth muscle contractions. A variety of chemically distinct calcium antagonists, viz. bepridil, diltiazem, isradipine (PN 200-110), nifedipine, and verapamil, non-competitively inhibited the contractions. Diltiazem was most potent (-logIC50 = 8.30) and bepridil least potent (-logIC50 = 6.19) in inhibiting the contractions. The findings conclude with the presence of pharmacologically distinct receptor-operated calcium-channels, besides the potential-dependent calcium-channels, in the rabbit jejunum.
使用毒蕈碱激动剂卡巴胆碱作为刺激剂，对离体的自发性节律性兔空肠中的钙通道进行了研究。卡巴胆碱未能产生平滑肌收缩的特征性相性和紧张性成分。多种化学结构不同的钙拮抗剂，即苄普地尔、地尔硫䓬、伊拉地平（PN 200 - 110）、硝苯地平及维拉帕米，非竞争性抑制了收缩。地尔硫䓬抑制收缩的作用最强（-logIC50 = 8.30），苄普地尔最弱（-logIC50 = 6.19）。研究结果表明，除了电压依赖性钙通道外，兔空肠中还存在药理学特性不同的受体操纵性钙通道。
