Afione S, Duvilanski B, Seilicovich A, Lasaga M, Díaz M C, Debeljuk L
Centro de Investigaciones en Reproducción, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
Brain Res Bull. 1990 Aug;25(2):245-9. doi: 10.1016/0361-9230(90)90068-b.
The effects of serotonin (5-HT) and its precursor, 5-hydroxytryptophan (5-HTP) on the GABAergic system in the mediobasal hypothalamus (MBH) and the anterior pituitary were studied. The IP administration of 5-HTP produced a transient increase (only at 45 min after the injection) in glutamate decarboxylase activity (GAD) of MBH and in GABA concentration in anterior pituitary. Besides, 5-HTP administration increased the in vitro evoked GABA release from MBH. The administration of 5-HTP to hypophysectomized rats partially reversed the inhibitory effects of hypophysectomy on GABA concentration in MBH. We also examined the direct effect of 5-HT on some parameters on the hypothalamic GABAergic system. The presence of 5-HT in the incubation medium increased GAD activity and evoked GABA release from MBH. These observations indicate that the serotoninergic stimulation of the hypothalamic GABAergic system could be a direct effect which may, at least partially, be independent of the feedback mechanism induced by prolactin on the GABAergic neurons. The serotoninergic increase of prolactin secretion could be accomplished through stimulation of the hypothalamic GABAergic transmission.
研究了血清素（5-羟色胺，5-HT）及其前体5-羟色氨酸（5-HTP）对中基底下丘脑（MBH）和垂体前叶GABA能系统的影响。腹腔注射5-HTP可使MBH的谷氨酸脱羧酶活性（GAD）和垂体前叶的GABA浓度短暂升高（仅在注射后45分钟）。此外，给予5-HTP可增加MBH体外诱发的GABA释放。给垂体切除的大鼠注射5-HTP可部分逆转垂体切除对MBH中GABA浓度的抑制作用。我们还研究了5-HT对下丘脑GABA能系统某些参数的直接影响。孵育培养基中5-HT的存在增加了GAD活性，并诱发了MBH的GABA释放。这些观察结果表明，下丘脑GABA能系统的5-羟色胺能刺激可能是一种直接作用，至少部分独立于催乳素对GABA能神经元诱导的反馈机制。5-羟色胺能增加催乳素分泌可能是通过刺激下丘脑GABA能传递来实现的。
