Nielsen-Kudsk J E
Acta Pharmacol Toxicol (Copenh). 1985 Jan;56(1):14-9. doi: 10.1111/j.1600-0773.1985.tb01247.x.
Effects of theophylline on contractions induced by relevant physiological agents in tubular segments of small human placental arteries were measured in an isometric myograph. Theophylline 10(-7) - 3 X 10(-3)M caused marked relaxation of steady contractions produced by prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 (PGE2), vasopressin or potassium. EC50 for theophylline relaxation of the PGF2 alpha - contraction was 1.6 X 10(-4) M. Emax was 91.5% relaxation. Theophylline was less potent in relaxing the potassium induced contraction. Pretreatment experiments with 10(-4) and 10(-3)M theophylline showed a pronounced decrease in contractile Emax-values for PGF2 alpha, PGE2 and vasopressin as a possible indication of non-competitive antagonism. The results motivate further studies to elucidate possible effects of theophylline and other xanthines on the vascular resistance and blood flow in placenta.
在等长肌动描记器中测量了氨茶碱对人胎盘小动脉管段中相关生理介质诱导的收缩的影响。10(-7)-3×10(-3)M的氨茶碱可使前列腺素F2α（PGF2α）、前列腺素E2（PGE2）、血管加压素或钾诱导的稳定收缩明显舒张。氨茶碱舒张PGF2α收缩的EC50为1.6×10(-4)M。最大舒张率（Emax）为91.5%。氨茶碱舒张钾诱导收缩的效力较弱。用10(-4)和10(-3)M氨茶碱进行的预处理实验显示，PGF2α、PGE2和血管加压素的收缩Emax值显著降低，这可能是非竞争性拮抗作用的一个指标。这些结果促使进一步研究以阐明氨茶碱和其他黄嘌呤对胎盘血管阻力和血流的可能影响。
