目的 研究左旋千金藤啶碱 (l- SPD)对β肾上腺素受体的作用。方法 应用放射配体结合实验 ,通过竞争[3H]双氢烯丙洛尔 ([3H]DHA)特异性结合 ,研究 l- SPD对 β肾上腺素受体的亲和力 ;在离体猪冠状动脉环实验中 ,观察 l- SPD对 β肾上腺素受体的拮抗作用。结果 l- SPD能竞争 [3H]DHA和兔肺细胞膜的结合部位 ,其 K i值为(5 .75± 0 .5 6 ) μmol/ L;l- SPD使去甲肾上腺素 (NA)对数累加量效曲线 (L CCRC)右移又压低 ,其 PA2 和 PD′2 值分别为 7.2 1± 0 .78,5 .32± 0 .13,而普萘洛尔 (Pro)使 NA的 L CCRC平行右移 ,PA2 值 9.19± 0 .17。结论 l- SPD对β受体有拮抗作用。此外 ,对其它受体可能也有影响。

Object To study the effect of l-stepholidine (l-SPD) on?β-adrenoceptors. Methods The affinity of l-SPD to?β-adrenoceptors was investigated by radioligand binding assay by means of competitive [3H]?labelled Dihydro-Aprenolol ([3H]?DHA) specific binding. The antagonism of l-SPD on?β-adrenoceptors was tested on pig coronary artery rings in vitro. Results [3H] DHA binding assay showed that l-SPD specifically displayed binding affinity to?β-adrenoceptors. The Ki value was (5.75±0.56)μmol/L; the logarithmic cumulative concentration-response curves (LCCRC) of l-SPD for NA on the pig coronary artery rings showed that the position of curves shifted to the right and the crest depressed. The values of pA2?an pD′2?were 7.21±0.78 and 5.32±0.13 respectively. As a control, propranolol (Pro) could shift the curves parallelly to the right and the pA2?value of Pro was 9.19±0.17. Conclusion The results suggested that l-SPD is a?β-adrenoceptor antagonist and has affinities to more than one kind of receptor.