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目的:探讨吗啡戒断反应对血管反应性及其细胞内信号转导的影响。方法:大鼠注射递增剂量的吗啡两周后iv纳洛酮催瘾,记录乙酰胆碱(Ach)的降压效应。用含不同药物的Kreb’s液灌流大鼠离体肠系膜血管床。AR-CM-MIC阳离子测定系统检测培养牛胸主动脉内皮细胞(aec)和血管平滑肌细胞(smc)胞浆内游离钙([Ca~(2+)]_i)。计算smc呈磷酸化cAMP反应元件结合蛋白(Phospho-CREB)免疫阳性反应的比例。结果:纳洛酮iv 2mg/kg催瘾后钝化的Ach降压效应同催瘾前一致。以纳洛酮25μmol/L取代灌流液所含吗啡20μmol/L使成瘾大鼠肠系膜血管的去甲肾上腺素(NE)升压效应的EC_(50)(μmol/L)从2.06±0.38降至1.14±0.21(n=8,P<0.01),而吗啡40μmol/L完全预防NE的作用。即时加入吗啡后对照组血管平滑肌细胞内[Ca~(2+)]_i反应不一。纳洛酮使2/3的吗啡预处理组的血管平滑肌细胞内[Ca~(2+)]_i显著升高,呈Phospho-CREB免疫阳性反应的比例也因之增加。部分内皮细胞的[Ca~(2+)]_i明显下降。结论:纳洛酮增加慢性吗啡处理大鼠血管的反应性可能与血管平滑肌细胞内钙增加有关,并伴有cAMP反应元件结合蛋白的磷酸化增强。
Objective: To investigate the effects of morphine withdrawal response on vascular reactivity and intracellular signal transduction. Methods: Rats were injected with increasing doses of morphine two weeks later, and naloxone was withdrawn. The antihypertensive effect of acetylcholine (Ach) was recorded. Rats with isolated mesenteric vascular beds were perfused with Kreb’s solution containing different drugs. AR-CM-MIC assay was used to detect intracellular free calcium ([Ca2 +] i) in cultured bovine aortic endothelial cells (aec) and vascular smooth muscle cells (smc). The percentage of smc-positive phosphorylated cAMP response element-binding protein (Phospho-CREB) immunoreactivity was calculated. Results: The attenuated Ach hypotensive effect of naloxone iv 2 mg / kg after passivation was consistent with that before withdrawal. The EC50 (μmol / L) of norepinephrine (NE) in the mesenteric vessels of addicted rats was decreased from 2.06 ± 0.38 to 20 μmol / L morphine with 25 μmol / L naloxone. 1.14 ± 0.21 (n = 8, P <0.01), while morphine 40 μmol / L completely prevented the effect of NE. Immediately after adding morphine, the control group had different responses to [Ca ~ (2 +)] _ i in the vascular smooth muscle cells. Naloxone increased the [Ca ~ (2 +)] _i in 2/3 morphine preconditioning group and increased the proportion of Phospho-CREB immunopositive reaction. Some endothelial cells [Ca ~ (2 +)] _i significantly decreased. CONCLUSION: Naloxone increases the reactivity of blood vessels in chronic morphine-treated rats, which may be related to the increase of calcium in vascular smooth muscle cells, accompanied by increased phosphorylation of cAMP response element-binding protein.