茶碱和去氧肾上腺素对心脏舒张的影响。
Theophylline and phenylephrine effects on cardiac relaxation.
作者信息
Benfey B G
出版信息
Br J Pharmacol. 1977 Jan;59(1):75-81. doi: 10.1111/j.1476-5381.1977.tb06979.x.
In the driven isolated left atrium of the rabbit theophylline shortened relaxation time in a similar manner to isoprenaline and histamine. 2 Phenylephrine lengthened relaxation time in a similar manner to calcium. 3 Theophylline caused phenylephrine to shorten relaxation time, which was inhibited by a beta-adrenoceptor blocking drug, but theophylline did not potentiate the effect of phenylephrine on peak tension. 4 Theophylline separated drug effects on cardiac relaxation and contraction: in the presence of theophylline at a low calcium concentration, phenylephrine shortened relaxation time by beta-adrenoceptor stimulation and increased peak tension by alpha-adrenoceptor stimulation. At a high calcium concentration, theophylline potentiated the effect of isoprenaline, histamine and phenylephrine on relaxation time but inhibited the effect on peak tension.
在兔的驱动性离体左心房中，茶碱缩短舒张时间的方式与异丙肾上腺素和组胺相似。2 去氧肾上腺素延长舒张时间的方式与钙相似。3 茶碱使去氧肾上腺素缩短舒张时间，这一作用被一种β-肾上腺素能受体阻断药所抑制，但茶碱并未增强去氧肾上腺素对峰值张力的作用。4 茶碱区分了药物对心脏舒张和收缩的作用：在低钙浓度且存在茶碱的情况下，去氧肾上腺素通过刺激β-肾上腺素能受体缩短舒张时间，并通过刺激α-肾上腺素能受体增加峰值张力。在高钙浓度时，茶碱增强了异丙肾上腺素、组胺和去氧肾上腺素对舒张时间的作用，但抑制了对峰值张力的作用。
Zotero 插件