Ahlner J, Axelsson K L, Ekstram-Ljusegren M, Friedman R L, Grundström N, Karlsson J O, Andersson R G
Department of Clinical Pharmacology, University Hospital, Linköping, Sweden.
Pharmacol Toxicol. 1988 Mar;62(3):155-8. doi: 10.1111/j.1600-0773.1988.tb01864.x.
Low concentrations (less than 1 nM) of glyceryl trinitrate (GTN) induced a considerable relaxation of bovine mesenteric arteries (BMA) brought to sustained contraction by the addition of phenylephrine. The concentration-response curve of GTN showed a biphasic pattern with a high and a low affinity component. Pretreatment with pertussis toxin (IAP) attenuated the high affinity relaxant component, but not the low affinity component or the relaxation induced by NaNO2. A polyclonal antibody to IAP counteracted the effect of the toxin on the GTN-response. Low concentrations of GTN increased the cGMP level in BMA via activation of the high affinity pathway. This effect was also inhibited in preparations pretreated with IAP. It is suggested from the present study that GTN induces relaxation of vascular smooth muscle via two separate pathways, the high affinity pathway might involve a receptor-complex interaction with a regulatory protein.
低浓度（低于1纳摩尔）的甘油三硝酸酯（GTN）可使因加入去氧肾上腺素而持续收缩的牛肠系膜动脉（BMA）出现显著舒张。GTN的浓度-反应曲线呈双相模式，具有高亲和力和低亲和力两个成分。百日咳毒素（IAP）预处理可减弱高亲和力舒张成分，但不影响低亲和力成分或亚硝酸钠诱导的舒张。针对IAP的多克隆抗体可抵消毒素对GTN反应的影响。低浓度的GTN通过激活高亲和力途径增加BMA中的环鸟苷酸（cGMP）水平。在用IAP预处理的制剂中，这种作用也受到抑制。本研究表明，GTN通过两条独立途径诱导血管平滑肌舒张，高亲和力途径可能涉及受体复合物与一种调节蛋白的相互作用。
