METHODS: Male Wistar rats were euthanized to isolate the superior mesenteric artery for isometric tension recordings. NO levels were measured using the DAF-FM/DA dye, and cyclic guanosine monophosphate (cGMP) levels were determined using a cGMP-ELISA Kit.
RESULTS: NONO2P presented a similar maximum efficacy to SNP. The free radical of NO (NO•) scavengers (PTIO; 100 μM and hydroxocobalamin; 30 μM) and nitroxyl anion (NO-) scavenger (L-cysteine; 3 mM) decreased relaxations promoted by NONO2P. The presence of the specific soluble guanylyl cyclase (sGC) inhibitor (ODQ; 10 μM) nearly abolished the vasorelaxation. The cGMP-dependent protein kinase (PKG) inhibition (KT5823; 1 μM) attenuated the NONO2P relaxant effect. The vasorelaxant response was significantly attenuated by blocking inward rectifying K+ channels (Kir), voltage-operated K+ channels (KV), and large conductance Ca2+-activated K+ channels (BKCa). NONO2P-induced relaxation was attenuated by cyclopiazonic acid (10 μM), indicating that sarcoplasmic reticulum Ca2+-ATPase (SERCA) activation is involved in this relaxation. Moreover, NONO2P increased NO levels in endothelial cells and cGMP production.
CONCLUSIONS: NONO2P induces vasorelaxation with the same magnitude as SNP, releasing NO• and NO-. Its vasorelaxant effect involves sGC, PKG, K+ channels opening, and SERCA activation, suggesting its potential as a therapeutic option for CVD.
方法:对雄性Wistar大鼠实施安乐死以分离肠系膜上动脉以进行等距张力记录。使用DAF-FM/DA染料测量NO水平,使用cGMP-ELISA试剂盒测定环磷酸鸟苷(cGMP)水平。
结果:NONO2P表现出与SNP相似的最大功效。NO(NO•)清除剂(PTIO;100μM和羟钴胺素;30μM)和硝酰基阴离子(NO-)清除剂(L-半胱氨酸;3mM)的自由基降低了NONO2P促进的弛豫。特异性可溶性鸟苷酸环化酶(sGC)抑制剂(ODQ;10μM)的存在几乎消除了血管舒张。cGMP依赖性蛋白激酶(PKG)抑制(KT5823;1μM)减弱NONO2P松弛作用。通过阻断内向整流K通道(Kir),血管松弛反应显着减弱,电压操作K+通道(KV),大电导Ca2+激活K+通道(BKCa)。环吡嗪酸(10μM)减弱了NONO2P诱导的弛豫,表明肌浆网Ca2-ATPase(SERCA)激活参与了这种松弛。此外,NONO2P增加内皮细胞中的NO水平和cGMP产生。
结论:NONO2P诱导血管舒张的幅度与SNP相同,释放NO•和NO-。它的血管舒张作用涉及sGC,PKG,K+通道打开,和SERCA激活,提示其作为心血管疾病治疗选择的潜力。