摘要
目的:观察黄芪对家兔心房收缩力及心房钠尿肽分泌的影响。方法:采用家兔离体心房灌流模型,处理0.002,0.002 5,0.003 g.L-1的黄芪水提取液观察家兔心房收缩力及心房钠尿肽分泌的变化,并选择最佳剂量探讨其作用机制。心房钠尿肽含量的测定采用放射免疫法。结果:3个剂量的黄芪水提取液使离体家兔心房每搏输出量由给药前的(694.70±0.01)μL.g-1分别增加到(1 003.00±8.80),(1 120.00±17.71),(1 195.00±8.21)μL.g-1(与给药前比较,分别P<0.05;P<0.01及P<0.001);并使心房搏动压由给药前的(0.82±0.01)kPa分别增加至(0.86±0.01),(0.96±0.01),(1.02±0.01)kPa(与给药前比较,分别P<0.01;P<0.001及P<0.001),且呈现浓度依赖性特征,表明黄芪可增加家兔心房收缩力。0.002 5 g.L-1黄芪水提取液显著抑制心房钠尿肽的分泌[给药前心房钠尿肽含量为(18.74±0.02)ng.min-1.g-1,给药后为(12.97±0.14)ng.min-1.g-1;与给药前比较P<0.001]。L-型Ca2+通道阻断剂硝苯地平(1.0μmol.L-1)及逆向Na+-Ca2+交换体抑制剂KB-R 7943(10.0μmol.L-1)阻断了黄芪增强心房收缩力的作用,但均未能改变黄芪对心房钠尿肽分泌的抑制效应。结论:黄芪主要通过影响L-型Ca2+通道及Na+-Ca2+交换体增强心房收缩力,并对心房钠尿肽分泌具有抑制性调节作用。
Objective: To define the effects of Astragalus membranaceus on the atrial dynamics and ANP secretion in the perfused beating rabbit atria. Method: The experiments have been done in isolated perfused beating rabbit atria. ANP was measured by radioimmunoassay in the atrial perfusate in real-time base. Result: A. membranaceus (2. 0, 2. 5, 3.0μL·g^-1 ) could increase atria stroke volume from (694. 70 ± 0. 01 ) μL·g^-1 ( p 〈 0. 05 ) to ( 1 003.00 ± 8. 80)μL·g^-1( p 〈 0. 001 ) ; ( 1120. 00 ±17.71 )μL·g^-1 and (1 195.00± 8.21 ) μL·g^-1( p 〈 0. 001 ), respectively, and its could difference increase atrial pulse pressure from (0. 82 ± 0.01) kPato (0.86±0.01) kPa (P〈0.01); (0.96 ±0.01) kPa (P 〈0.001) and (1.02 ±0.01) kPa (P 〈0.001), respectively; A. membranaceus obviously increased rabbit atrial dynamics with dose-dependent manner. Simultaneously, A. membranaceus inhibited ANP secretion. Nifedipine ( 1.0μmol· L^-1 ), a L-type Ca^2+ channel inhibitor, and KB-R 7943 ( 10. 0μmol· L^-1 ), an inhibitor of reversed Na^+ -Ca^2+ exchanger, blocked the effects of A. membranaceus-induced augmentation of atrial dynamics but failed to modulation the inhibition of A. membranaceus on ANP secretion. Conclusion: A. membranaceus increases the atrial dynamics via Na^+ -Ca^2+ exchanger and L-type Ca^2+ channel and negatively modulates ANP secretion in beating rabbit atria.
出处
《中国中药杂志》
CAS
CSCD
北大核心
2008年第19期2226-2229,共4页
China Journal of Chinese Materia Medica