Chinellato A, Froldi G, Caparrotta L, Ragazzi E
Department of Pharmacology, University of Padova, Italy.
Life Sci. 1998;62(6):479-90. doi: 10.1016/s0024-3205(97)01144-2.
Different receptors mediating the release of endothelium-derived nitric oxide (EDNO) have been identified at endothelial level. In the present study we aimed to characterise, on rabbit aorta by means of pharmacological tools, the generation of EDNO by receptors located on endothelial cell membrane (M3, P2u, P2y) and by direct activation of Ca2+ entry into the endothelial cell. Four vasodilating drugs were tested (acetylcholine, UTP, A23187 and 2-methyl-thio-ATP); they were active only if the endothelial layer was intact, suggesting that they act through endothelial receptors. The effect of different nitric oxide synthase (NOS) inhibitors (0.1 mM: L- and D-NAME, L-NMMA, L-NIO and 7-NI) was investigated on NO-mediated relaxation induced by the relaxants in vessels with intact endothelium. NOS inhibitors differently affected relaxation mediated by the vasoactive drugs in isolated rabbit aorta. Reversibility of the inhibition by using a fixed concentration of L-arginine (0.1 mM) was different depending on the relaxing drug and NOS-inhibitor. The data obtained support the coexistence in aortic vessel of more than one endothelial cell NOS isoform, each provided with different receptor coupling.
在内皮水平已鉴定出介导内皮衍生一氧化氮（EDNO）释放的不同受体。在本研究中，我们旨在通过药理学方法在兔主动脉上表征位于内皮细胞膜上的受体（M3、P2u、P2y）以及通过直接激活Ca2+进入内皮细胞来产生EDNO的情况。测试了四种血管舒张药物（乙酰胆碱、UTP、A23187和2-甲基硫代-ATP）；它们仅在内皮层完整时才有活性，这表明它们通过内皮受体起作用。研究了不同的一氧化氮合酶（NOS）抑制剂（0.1 mM：L-和D-NAME、L-NMMA、L-NIO和7-NI）对完整内皮血管中由舒张剂诱导的NO介导的舒张作用的影响。NOS抑制剂对离体兔主动脉中血管活性药物介导的舒张作用有不同影响。使用固定浓度的L-精氨酸（0.1 mM）进行抑制的可逆性因舒张药物和NOS抑制剂而异。获得的数据支持主动脉血管中存在不止一种内皮细胞NOS同工型，每种同工型具有不同的受体偶联。
