血小板活化因子对原位血液灌注大鼠肠系膜血管收缩的抑制作用。

Inhibition of vasoconstriction by platelet activating factor in the in situ blood perfused rat mesentery.

Gerkens J F

Discipline of Clinical Pharmacology, University of Newcastle, New South Wales, Australia.

Clin Exp Pharmacol Physiol. 1989 Mar;16(3):161-7. doi: 10.1111/j.1440-1681.1989.tb01540.x.

Abstract

Perfusion pressure was measured in the in situ mesentery of anaesthetized rats perfused with blood at a constant 2 mL/min. 2. Increases in perfusion pressure were produced by mesenteric peri-arterial nerve stimulation at 10 Hz for 5 s at 2 min intervals and by bolus intra-arterial injections of the vasoconstrictors noradrenaline, angiotensin II and 5-hydroxytryptamine. 3. The intra-arterial infusion of platelet-activating factor (PAF) to produce a blood concentration of 3 X 10(-10) mol/L inhibited all responses to a similar extent. Intra-arterial prazosin (1-5 X 10(-9) mol/L), however, preferentially reduced responses to nerve stimulation and noradrenaline. 4. PAF at concentrations from 3 X 10(-11) to 10(-9) mol/L produced increasing inhibition of vasoconstrictor responses to nerve stimulation. The dose-response to PAF was shifted to the right by the concomitant intra-arterial infusion of the PAF antagonist SRI 63-441. 5. PAF at very low concentrations in vivo inhibits mesenteric vasoconstriction, produced by sympathetic nerve stimulation or various agonists, by a PAF-receptor mediated vasodilatation of the mesenteric vasculature.

摘要

在以2毫升/分钟的恒定速率用血液灌注的麻醉大鼠的原位肠系膜中测量灌注压。2. 通过每隔2分钟以10赫兹频率刺激肠系膜动脉周围神经5秒以及通过动脉内推注血管收缩剂去甲肾上腺素、血管紧张素II和5-羟色胺来产生灌注压升高。3. 动脉内输注血小板活化因子（PAF）以产生3×10⁻¹⁰摩尔/升的血药浓度，在相似程度上抑制所有反应。然而，动脉内注射哌唑嗪（1 - 5×10⁻⁹摩尔/升）优先降低对神经刺激和去甲肾上腺素的反应。4. 浓度为3×10⁻¹¹至10⁻⁹摩尔/升的PAF对神经刺激引起的血管收缩反应的抑制作用增强。伴随动脉内输注PAF拮抗剂SRI 63 - 441使PAF的剂量反应曲线右移。5. 体内极低浓度的PAF通过PAF受体介导的肠系膜血管舒张，抑制由交感神经刺激或各种激动剂引起的肠系膜血管收缩。