Yamada T, Nakao K, Itoh H, Morii N, Shiono S, Sakamoto M, Sugawara A, Saito Y, Mukoyama M, Arai H
Department of Medicine, Kyoto University School of Medicine, Japan.
Endocrinology. 1988 Mar;122(3):985-90. doi: 10.1210/endo-122-3-985.
To elucidate the role of leumorphin, a kappa-agonist derived from proenkephalin-B (neoendorphin/dynorphin precursor), in the control of arginine vasopressin (AVP) secretion, we examined the effects of intracerebroventricular (icv) administration of leumorphin on AVP secretion under basal and stimulated conditions in conscious unrestrained rats. Intracerebroventricular injection of leumorphin (60 or 600 pmol) significantly inhibited basal AVP secretion. In 72-h water-deprived rats, icv injection of leumorphin (60 or 600 pmol) also suppressed AVP secretion in a dose-dependent manner. The AVP response induced by icv injection of angiotensin II (100 pmol) was significantly decreased by the simultaneous icv injection of leumorphin (6-600 pmol) in a dose-dependent manner. Intracerebroventricular administration of leumorphin (600 pmol) also reduced the AVP secretion stimulated by icv injection of carbachol (50 pmol). Intravenous pretreatment with naloxone (0.5 mg/kg BW) diminished the inhibitory action of leumorphin (60 pmol) on AVP secretion. However, no effect on AVP secretion was observed after iv injection of leumorphin (600 pmol). These results indicate that leumorphin possesses a potent inhibitory effect on AVP secretion, suggesting its important role in the regulation of AVP secretion in the brain.
为阐明亮啡肽（一种源自脑啡肽原B的κ激动剂，新内啡肽/强啡肽前体）在精氨酸加压素（AVP）分泌调控中的作用，我们在清醒自由活动的大鼠基础和刺激条件下，研究了脑室内（icv）注射亮啡肽对AVP分泌的影响。脑室内注射亮啡肽（60或600 pmol）显著抑制基础AVP分泌。在72小时禁水的大鼠中，脑室内注射亮啡肽（60或600 pmol）也以剂量依赖方式抑制AVP分泌。同时脑室内注射亮啡肽（6 - 600 pmol）以剂量依赖方式显著降低脑室内注射血管紧张素II（100 pmol）诱导的AVP反应。脑室内注射亮啡肽（600 pmol）也减少了脑室内注射卡巴胆碱（50 pmol）刺激的AVP分泌。静脉注射纳洛酮（0.5 mg/kg体重）预处理减弱了亮啡肽（60 pmol）对AVP分泌的抑制作用。然而，静脉注射亮啡肽（600 pmol）后未观察到对AVP分泌的影响。这些结果表明亮啡肽对AVP分泌具有强大的抑制作用，提示其在脑内AVP分泌调节中起重要作用。
