Itoh H, Nakao K, Yamada T, Morii N, Shiono S, Sakamoto M, Sugawara A, Saito Y, Mukoyama M, Arai H
Department of Medicine, Kyoto University School of Medicine, Japan.
Am J Hypertens. 1988 Jul;1(3 Pt 1):256-61. doi: 10.1093/ajh/1.3.256.
To investigate the role of leumorphin, a kappa-opioid agonist derived from proenkephalin B (neoendorphin/dynorphin precursor) in the central cardiovascular control, the effects of intracerebroventricular (ICV) administration of leumorphin on basal blood pressure and angiotensin II (AII)-stimulated pressor response were examined in conscious unrestrained rats. The ICV injection of 0.06 and 0.6 nmol of leumorphin caused a significant decrease in basal blood pressure (delta mean arterial pressure (MAP): -6.5 +/- 2.7 and -7.2 +/- 1.7 mm Hg, respectively). The ICV injection of AII (0.1 nmol) elicited a pressor response (delta MAP: 21.4 +/- 1.1 mm Hg). This pressor response was significantly reduced by the simultaneous administration of leumorphin, and furthermore, the blood pressure was lowered below the basal level. These depressor actions of leumorphin were partially antagonized by the preadministration of naloxone, an opiate antagonist. These results together with our previous works on the potent inhibitory actions of leumorphin on drinking and vasopressin secretion suggest the possible involvement of leumorphin in the central regulation of blood pressure and body fluid homeostasis.
为研究亮啡肽（一种源自前脑啡肽B（新内啡肽/强啡肽前体）的κ阿片受体激动剂）在中枢心血管控制中的作用，在清醒自由活动的大鼠中检测了脑室内（ICV）注射亮啡肽对基础血压和血管紧张素II（AII）刺激的升压反应的影响。脑室内注射0.06和0.6 nmol亮啡肽可使基础血压显著降低（平均动脉压（MAP）变化分别为：-6.5±2.7和-7.2±1.7 mmHg）。脑室内注射AII（0.1 nmol）可引发升压反应（MAP变化：21.4±1.1 mmHg）。同时注射亮啡肽可显著降低该升压反应，此外，血压还会降至基础水平以下。亮啡肽的这些降压作用部分被阿片受体拮抗剂纳洛酮预先给药所拮抗。这些结果以及我们之前关于亮啡肽对饮水和血管升压素分泌有强效抑制作用的研究表明，亮啡肽可能参与血压和体液稳态的中枢调节。
