Shimatsu A, Tanoh T, Tsuji I, Yanaihara N, Imura H
Department of Internal Medicine, Kyoto University Faculty of Medicine, Japan.
Yakubutsu Seishin Kodo. 1993 Jun;13(3):111-7.
The possible role and mechanism of central nicotinic cholinergic receptors in regulating growth hormone (GH) secretion were investigated in conscious, unrestrained male rats. The administration of galanin (GAL), a neuropeptide, GH-releasing hormone (GHRH) and UK 14304, an alpha-2 adrenergic agonist, caused increases in plasma GH levels. Pretreatment of the animals with hexamethonium significantly reduced GAL- and GHRH-induced GH secretion, but UK 14304-induced GH release was not affected. Neosurugatoxin, a nicotinic cholinergic neurotoxin, partially inhibited GAL-induced GH release. Pretreatment with neostigmine elevated basal plasma GH levels and partially inhibited GAL-induced GH secretion. However, GHRH- and UK 14304-induced GH release was additive to the effect of neostigmine. Yohimbine inhibited GH release induced by UK 14304, GAL and GHRH. Neostigmine-induced GH secretion was partially inhibited by yohimbine and phenoxybenzamine. These findings suggest that central nicotinic receptors have a stimulatory role in regulating GH secretion and that the nicotinic cholinergic system coupled with the alpha-2 adrenergic mechanism is involved in GH secretion induced by galanin in conscious rats.
在清醒、无拘束的雄性大鼠中，研究了中枢烟碱型胆碱能受体在调节生长激素（GH）分泌中的可能作用及机制。给予神经肽甘丙肽（GAL）、生长激素释放激素（GHRH）和α-2肾上腺素能激动剂UK 14304后，血浆GH水平升高。用六甲铵预处理动物可显著降低GAL和GHRH诱导的GH分泌，但UK 14304诱导的GH释放不受影响。烟碱型胆碱能神经毒素新海葵毒素部分抑制GAL诱导的GH释放。用新斯的明预处理可提高基础血浆GH水平，并部分抑制GAL诱导的GH分泌。然而，GHRH和UK 14304诱导的GH释放与新斯的明的作用具有相加性。育亨宾抑制UK 14304、GAL和GHRH诱导的GH释放。新斯的明诱导的GH分泌被育亨宾和酚苄明部分抑制。这些发现表明，中枢烟碱型受体在调节GH分泌中具有刺激作用，并且烟碱型胆碱能系统与α-2肾上腺素能机制参与了清醒大鼠中甘丙肽诱导的GH分泌。
