Vascular actions of purines in the foetal circulation of the human placenta

摘要: Abstract 1. The vasoactive effects of adenosine triphosphate (ATP), and other purines in the foetal circulation human placenta were examined. Single lobules bilaterally perfused vitro with Krebs buffer (maternal sides 5 ml min-1 each, 95% O2:5% CO2, 37 degrees C). Changes vascular tone assessed by recording perfusion pressure during constant infusion each purine. To allow vasodilator effects, submaximal vasoconstriction was induced concomitant prostaglandin F2 alpha (0.7-2.0 mumol l-1). 2. ATP (1.0-100 l-1) usually caused concentration-dependent reductions pressure. However, biphasic initial transient increases, or only increases sometimes observed. Falls significantly reduced addition to perfusate NG-nitro-L-arginine (L-NOARG) (100 but not NG-nitro-D-arginine (D-NOARG) They influenced indomethacin (10 L-arginine 3. Adenosine (0.01-1.0 mmol consistently pressure, this effect being indomethacin. L-NOARG, D-NOARG, potency approximately three fold. L-Arginine, D-arginine enhanced its a similar amount. 4. 2-Methylthio-ATP, selective P2 gamma agonist 50 times more potent than as agent, always causing decreases pressure.(ABSTRACT TRUNCATED AT 250 WORDS)