Study on vasorelaxations of oxyphenamone and its mechanism / 药学学报

ABSTRACT

<p><b>AIM</b>To study the vasorelaxation action of oxyphenamone (Oxy) and its mechanism.</p><p><b>METHODS</b>The contractile response of isolated rabbit renal, femoral and mesentery artery preparations was determined.</p><p><b>RESULTS</b>Oxy was shown to inhibit the contractile force of renal, femoral and mesentery arteries induced by phenylephrine in a concentration dependent manner. The vasorelaxation produced by Oxy was not attenuated by removal of the endothelium. Oxy (10(-6)-10(-4) mol.L-1) relaxed the contractions induced by KCl 30 mmol.L-1 as well as KCl 80 mmol.L-1, but the contraction curve of KCl 80 mmol.L-1 was shifted significantly to the right. Oxy in lower concentration (10(-6) and 5 x 10(-6) mol.L-1) increased the contractions induced by Ang II, and in middle concentration (10(-5) mol.L-1) it did not affect the contractions induced by Ang II. Whereas in higher concentration (5 x 10(-5) mol.L-1) it obviously inhibited the contractions induced by Ang II.</p><p><b>CONCLUSION</b>Oxy showed significant vasorelaxation to various vascular preparations, and its vasorelaxation action is endothelium independent. The mechanism of its vasorelaxations seems to be related with Ca2+ activated K+ channel (Kca channel) and Ca2+ channel in vascular smooth muscle cells but its true mechanism needs further study.</p>