Hemavathi K G, Bhatt J D, Amin D V, Gulati O D, Shah D S
Indian J Physiol Pharmacol. 1979 Oct-Dec;23(4):261-8.
The effects of papaverine MgCl2, cocaine, DNP, KCN and khellin on responses of some rabbit and rat tissues to CaCl2 were studied in vitro in a depolarizing medium. Guinea pig taenia coli preparation was used for comparison. In rabbit tracheal chain and vas deferens and guinea pig taenia coli preparations all spasmolytics shifted the concentration-response curves of CaCl2 to the right without affecting the maxima or slopes. In rat tracheal chain and vas deferens preparations all spasmolytics shifted the concentration-response curves of CaCl2 to the right. Furthermore all agents (except cocaine in tracheal chain preparations) depressed the maximum responses. The slopes were unaffected in either preparations. The initial competition and subsequent noncompetition observed in certain tissues is discussed in the light of the reported poor capacity of some tissues to retain Ca++ and the absence of releasable firmly bound Ca++ (11).
在去极化介质中对兔和大鼠的一些组织进行体外研究，观察了罂粟碱、氯化镁、可卡因、二硝基酚、氰化钾和凯林对氯化钙反应的影响。以豚鼠结肠带制备物作为对照。在兔气管链和输精管以及豚鼠结肠带制备物中，所有解痉药均使氯化钙的浓度-反应曲线右移，而不影响最大值或斜率。在大鼠气管链和输精管制备物中，所有解痉药也使氯化钙的浓度-反应曲线右移。此外，所有药物（气管链制备物中的可卡因除外）均降低最大反应。两种制备物中的斜率均未受影响。根据一些组织对钙离子保留能力较差以及不存在可释放的紧密结合钙离子的报道（11），讨论了在某些组织中观察到的初始竞争和随后的非竞争现象。
