Inhibitory action of bepridil (CERM-1978) on calcium binding to cardiac sarcolemma of guinea pig.
Inhibitory action of bepridil (CERM-1978) on calcium binding to cardiac sarcolemma of guinea pig.
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苯普地尔 (CERM-1978) 对豚鼠心脏肌膜钙结合的抑制作用。
DOI：
10.1016/0006-2952(81)90112-x
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发表时间：
1981
影响因子：
5.8
通讯作者：
Sperelakis,N
中科院分区：
文献类型：
--
作者：
Pang,DC;Sperelakis,N
苯丙地尔(CEM-1978)，1-(3-异丁氧基-2-苯基苯氨基)丙基吡咯烷盐酸盐，是一种无β-肾上腺素能受体阻断作用的新型抗心绞痛和抗心律失常药物。该药对犬心脏有负性变力作用[L-3]。在离体豚鼠心脏灌流中也证实了这一效应，抑制收缩的机制是由于收缩与兴奋的解偶联[4]。Vogel等人[4]也证明了苯丙地尔有两种作用。一种是抑制和阻断动作电位期间钙离子通过的心肌慢通道，导致张力的发展。苯普地尔的这种作用类似于维拉帕米，但苯普地尔的效力较弱。倍普地尔对心肌细胞的其他作用不太清楚，但它与抑制肌浆网钙释放是一致的。众所周知，在完整的心脏兴奋过程中，肌膜负责调节钙离子的内流。因此，为了探讨苯丙地尔负性变力作用的可能机制，我们测定了其对心肌肌膜钙结合部位的影响。并与另一种钙拮抗剂维拉帕米的作用进行比较。研究发现，与维拉帕米一样，苯普地尔抑制了钙离子与肌膜上一个低亲和力部位的结合。按Pang和Weglicki的方法分离豚鼠心肌肌膜。简而言之，该方法采用温和匀浆、0.6MKCI提取、差速和蔗糖密度梯度离心法。(Na‘，K’)-ATPase活性平均为25.2±0.7pmol.Mg-I。HR-‘。在150 mM氯化钠、2.7 mM氯化钾、1 mM氯化镁、1×10~(-6)~(-2)×10~(-1)M缓存存在下，测定心肌细胞膜上的钙结合。0.2pCiiml“‘CaCIJ，20 mM Tris，pH 7.4，肌膜(0.5mgiml)。将苯丙地尔溶于50%乙醇中，加入0.01ml，得到10hM和10J M的最终浓度。加入相同浓度的乙醇本身对钙结合无明显影响。肌膜在室温下孵育10min，然后在Eppendorf高速离心机中离心10min。将小球在0.1N NaOH中60“溶解1小时，并在液体闪烁系统中计数。为了纠正非特异性结合，在孵育液中加入10 mM的EGTA[乙二醇双-(氨基-乙烯)四乙酸酯]来代替非放射性的CaCIZ。从实验值中减去在该空白区域中测量的放射性。根据公式假定钙与肌膜的结合发生在两类位置上：Z(n，[Cal/K，)L(L+[Cal/K，)]，其中i=1或2；K=离解常数；n=结合位点的容量(61)。用计算机进行统计分析表明，这些数据与一类或三类结合位点都不相容。所有数据都是以均值表示的吗？如图1所示，在生理浓度的氯化钠(150 MM)、氯化钾(2.7 mM)和氯化镁(1 MM)存在下，钙被动地结合到心肌肌膜上。肌膜上含有两类钙结合部位。高亲和力中心的离解常数为1.5×10~(-5)M，比容量为0.45~2.0毫克分子/毫克分子。低亲和力中心的离解常数为3.3f0.3×10m3M，容量为54.0±3.2nmoles/mg。
Bepridil(CERM-1978), 1-(3-isobutoxy-2-benzylphenylamino) propyl pyrrolidine hydrochloride, is a new antianginal and antiarrhythmic agent without beta-adrenergic receptor blocking action. This drug exerts a negative inotropic effect in dog heart [l-3]. This effect has also been demonstrated in isolated perfused guinea pig hearts, and the mechanism for depression of contraction is due to uncoupling of contraction from excitation [4]. Vogel et al.[4] have also demonstrated that Bepridil exerts two actions. One is to depress and block the myocardial slow channels through which calcium ions pass during the action potential, leading to the development of tension. This action of Bepridil is similar to that of Verapamil, but Bepridil is less potent. The other action of Bepridil on the cardiac cells is less clear, but it is consistent with the depression of calcium release from the sarcoplasmic reticulum. It is well known that the sarcolemma is responsible for the regulation of the influx of calcium during the process of excitation in the intact heart. Thus, to examine the possible mechanism for the negative inotropic action of Bepridil, we have determined its effect on the calcium binding sites of isolated cardiac sarcolemma. The effect of Bepridil was compared with that of another calcium-antagonistic agent, namely, Verapamil. It was found that Bepridil, like Verapamil, depressed the calcium binding to a low affinity site on the sarcolemma. Cardiac sarcolemma from guinea pig was isolated according to the method of Pang and Weglicki [5]. In brief, this method used gentle homogenization, extraction with 0.6 M KCI, and differential and sucrose density gradient centrifugation. The membrane fractions were collected at the sucrose range of 38-42 percent(w/w), and the (Na’, K’)-ATPase activity averaged 25.2+ 0.7 pmoles. mg-I. hr-‘. Calcium binding to the cardiac sarcolemma was measured in the presence of 150 mM NaCI, 2.7 mM KCI, 1 mM MgClz, 1 x 10e6-2 x lo-’M CaCh. 0.2 pCiiml“‘CaCIJ, 20 mM Tris, pH 7.4, and sarcolemma (0.5 mgiml). Bepridil was dissolved in 50% ethanol and added in a total volume of 0.01 ml to give final concentrations of 10-h M and 10-j M. Addition of a similar concentration of ethanol by itself had no significant effect on calcium binding. Sarcolemma was incubated at room temperature for 1Omin and then was centrifuged for 10min in an Eppendorf high speed centrifuge. The pellet was dissolved in 0.1 N NaOH at 60” for 1 hr and counted in a liquid scintillation system. To correct for non-specific binding, 10 mM EGTA [ethyleneglycolbis-(amino-ethylene) tetra-acetate] was added to the incubation medium, in place of the nonradioactive CaCIZ. Radioactivity measured in this blank was subtracted from the experimental values. The data were litted to curves calculated on the assumption that the binding of calcium to the sarcolemma had taken place in two classes of sites according to the formula: Z (n,[Cal/K,) l (l+[Cal/K,), where i= 1 or 2; K= dissociation constant; and n= capacity of binding sites (61. Statistical analysis with a computer showed that the data were not compatible with either one or three classes of binding sites. All data are expressed as means? SEM of six experiments.As shown in Fig. 1, calcium bound passively to the cardiac sarcolemma in the presence of physiological concentrations of NaCl (150 mM), KC1 (2.7 mM), and MgClz (1 mM). Sarcolemma contained two classes of calcium binding sites. The high affinity sites had a dissociation constant of 1.5 Ifr 0.2 x 10m5 M and a capacity of 0.45 2 O. O6nmole/mg. The low affinity sites had a dissociation constant of 3.3 f 0.3 x 10m3 M and a capacity of 54.0? 3.2 nmoles/mg.
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大鼠心肌肌膜中的钙结合位点。
影响因子：
3.9
作者：
C. Limas
通讯作者：
C. Limas
正性肌力药物对钙与离体心脏肌膜结合的影响。
DOI：
--
发表时间：
1980
期刊：
Biochimica et Biophysica Acta
影响因子：
--
作者：
D. Pang
通讯作者：
D. Pang
苄普地尔、双嘧达莫、普萘洛尔对麻醉犬心脏活动和冠状静脉债务的影响比较。
DOI：
--
发表时间：
1977
期刊：
The´rapie (Paris)
影响因子：
--
作者：
M. Michelin;M. Cheucle;P. Duchêne
通讯作者：
P. Duchêne
心肌细胞表面、组织化学以及唾液酸和钙去除对其结构和细胞离子交换的影响
影响因子：
20.1
作者：
J. Frank;G. Langer;L. M. Nudd;K. Seraydarian
通讯作者：
K. Seraydarian
钙离子流入的代谢控制机制可以保护心室心肌细胞。
DOI：
10.1016/0002-9149(76)90428-8
发表时间：
1976
期刊：
The American journal of cardiology
影响因子：
--
作者：
Nick Sperelakis;Joel A. Schneider
通讯作者：
Joel A. Schneider