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目的 研究DDPH对α1 肾上腺素受体 (α1 AR)及其亚型的拮抗作用。方法 放射配体结合实验和离体血管收缩功能实验。结果 DDPH对12 5I BE2 2 5 4与大鼠脑皮质和脾脏α1 AR结合呈竞争性拮抗作用。pKI 值在两者间无显著性差别 ,Hill系数均接近于 1 0。在分别稳定表达α1A,α1B或α1D AR的克隆HEK2 93细胞中 ,其拮抗的pKI 值α1A和α1D比α1B AR高约 2倍 ,Hill系数均接近于 1 0。并拮抗去甲肾上腺素 (NE)介导大鼠主动脉 ,肾动脉和脾脏收缩的 pA2 值 ,在三者间无显著差别 ,斜率接近 1 0。结论 DDPH对α1 AR有竞争性拮抗作用 ,但其作用对α1 AR亚型无选择性。
Objective To investigate the antagonistic effect of DDPH on α1 adrenergic receptor (α1 AR) and its subtypes. Methods Radioligand binding assay and ex vivo vasoconstriction function test. Results DDPH showed a competitive antagonistic effect on 125I BE2 2 5 4 binding to rat cerebral cortex and spleen α1 AR. There was no significant difference between the pKI values and the Hill coefficients were close to 10. In the HEK2 93 cells stably expressing α1A, α1B or α1D AR, the antagonistic pKI values α1A and α1D were about 2 times higher than those of α1B AR, and the Hill coefficients were all close to 10. And antagonized the NEA-mediated pA2 contraction in rat aorta, renal artery and spleen. There was no significant difference among the three, and the slope was close to 10%. Conclusion DDPH has a competitive antagonistic effect on α1 AR, but its effect is not selective for α1 AR subtype.