Corresponding author: Universidade de São Paulo, Escola de Enfermagem de Ribeirão Preto, Laboratório de Farmacologia, Avenida Bandeirantes 3900, CEP 14040-902, Ribeirão Preto, SP, Brazil.
Alcohol Alcohol. 2013 Nov-Dec;48(6):657-66. doi: 10.1093/alcalc/agt057. Epub 2013 Jun 23.
We investigated the effects of chronic ethanol consumption on the cavernosal smooth muscle (CSM) reactivity to endothelin-1 (ET-1) and the expression of ET system components in this tissue.
Male Wistar rats were treated with heavy dose of ethanol (20% v/v) for 6 weeks. Reactivity experiments were performed in the isolated rat CSM. Plasma and CSM nitrate generation and also superoxide anion generation in rat CSM were measured by chemiluminescence. Protein and mRNA levels of pre-pro-ET-1, endothelin-converting enzyme-1 (ECE-1), ETA and ETB receptors, eNOS, nNOS and iNOS were assessed by western immunoblotting and quantitative real-time polymerase chain reaction, respectively.
Chronic ethanol consumption increased plasma ET-1 levels and the contractile response induced by this peptide in the isolated CSM. The relaxation induced by acetylcholine, but not IRL1620, a selective ETB receptor agonist, was reduced in CSM from ethanol-treated rats. BQ123, a selective ETA receptor antagonist, produced a rightward displacement of the ET-1 concentration-response curves in CSM from control, but not ethanol-treated rats. Reduced levels of nitrate were found in the plasma and CSM from ethanol-treated rats. Ethanol consumption increased superoxide anion generation in the rat CSM. The mRNA levels of pre-pro-ET-1, ECE-1, ETA and ETB receptors, eNOS, nNOS and iNOS were not altered by ethanol consumption. Protein levels of ET-1, ETA receptor and iNOS were higher in the CSM from rats chronically treated with ethanol.
The major findings of the present study are that heavy ethanol consumption increases plasma ET-1 levels and the contraction induced by the peptide in the CSM. Increased CSM reactivity to ET-1 and altered protein levels of ET-1 and ETA receptors could play a role in the pathogenesis of erectile dysfunction associated with chronic ethanol consumption.
我们研究了慢性乙醇摄入对海绵体平滑肌（CSM）对内皮素-1（ET-1）反应性的影响，以及该组织中 ET 系统成分的表达。
雄性 Wistar 大鼠接受大剂量乙醇（20% v/v）处理 6 周。在分离的大鼠 CSM 中进行反应性实验。通过化学发光法测量血浆和 CSM 硝酸盐生成以及大鼠 CSM 中超氧阴离子生成。通过 Western 免疫印迹和定量实时聚合酶链反应分别评估前原 ET-1、内皮素转化酶-1（ECE-1）、ETA 和 ETB 受体、eNOS、nNOS 和 iNOS 的蛋白和 mRNA 水平。
慢性乙醇摄入增加了血浆 ET-1 水平和分离的 CSM 中该肽诱导的收缩反应。乙酰胆碱诱导的松弛，但不是选择性 ETB 受体激动剂 IRL1620 的松弛，在乙醇处理大鼠的 CSM 中减少。选择性 ETA 受体拮抗剂 BQ123 使 ET-1 浓度-反应曲线在对照大鼠的 CSM 中产生右移，但在乙醇处理大鼠的 CSM 中则不然。发现乙醇处理大鼠的血浆和 CSM 中硝酸盐水平降低。乙醇摄入增加了大鼠 CSM 中超氧阴离子的生成。前原 ET-1、ECE-1、ETA 和 ETB 受体、eNOS、nNOS 和 iNOS 的 mRNA 水平不受乙醇摄入的影响。ET-1、ETA 受体和 iNOS 的蛋白水平在慢性乙醇处理大鼠的 CSM 中更高。
本研究的主要发现是，大量乙醇摄入增加了血浆 ET-1 水平和 CSM 中肽诱导的收缩。CSM 对 ET-1 的反应性增加以及 ET-1 和 ETA 受体的蛋白水平改变可能在与慢性乙醇摄入相关的勃起功能障碍发病机制中发挥作用。
