Growth hormone-releasing factor and neuroactive substances (galanin, neurotensin, dopamine)-containing neurons projecting to the median eminence of the rat.

1. 含有甘丙肽（GAL）和生长激素释放因子（GRF）的神经元向大鼠正中隆起投射-------通过True blue逆行转运和GAL免疫组化染色相结合的方法，鉴定了向正中隆起投射的GAL神经元。此外，用洗脱-保留法分析了GAL和生长激素释放因子（GRF）在弓状核（ARC）中的分布。在正中隆起注射True blue后，True blue标记的gal阳性细胞主要出现在ARC中。洗脱抑制结果显示，ARC中许多逆行标记的GAL神经元含有GRF。这些发现表明，将轴突发送到中央隆起的ARC中的GAL神经元亚群产生、储存和释放一种类似grf的肽。神经紧张素（NT）和含grf的神经元向大鼠正中隆起突起，逆行标记的NT神经元主要分布在ARC。脑室周围核和室旁核仅见少量标记的NT神经元。洗脱保留程序表明，在ARC腹侧标记的NT细胞中，平均有43%的细胞保留了GRF.3。多巴胺（DA）和含有grf的神经元投射到大鼠的正中隆起。ARC中约56%的酪氨酸羟化酶（TH）神经元被标记为真蓝，表明它们投射到正中隆起。洗脱保留程序显示，ARC腹外侧部分标记的TH细胞中平均有32%含有GRF。这些发现支持了ARC中多巴胺与GRF共表达的假设。

1. Galanin(GAL)and growth hormone-releasing factor(GRF)-containing neurons projecting to the median eminence of the rat ------- Through the combined demonstration of the retrograde transport of True blue and the immunohistochemical staining of GAL, the GAL neurons that project to the median eminence were identified. Moreover, the distribution of GAL and growth hormone-releasing factor(GRF)was analyzed in the arcuate nucleus(ARC)with an elution-restaining procedure. Following the injection of True blue into the median eminence, GAL-positive cells labeled with True blue were found mainly in the ARC. The elution-restaining results revealed that many retrogradely labeled GAL neurons in the ARC contained GRF. These findings suggest that a subpopulation of GAL neurons in the ARC sending axons to the median eminence produces, stores and releases a GRF-like peptide.2. Neurotensin(NT)and GRF-containing neurons projecting to the median eminence of the rat The retrogradely labeled NT neurons were found mainly in the ARC. Only a few'labeled NT neurons were seen in the periventricular and the paraventricular nuclei. The elution restaining procedur demonstrated that an average of 43% of the labeled NT cells in the ventral part of the ARC restained for GRF.3. Dopamine(DA)and GRF-containing neurons projecting to the median eminence of the rat. Approximately 56% of the tyrosine hydroxylase(TH)neurons in the ARC were labeled with True blue, indicating that they projected to the median eminence. The elution restaining procedure revealed that an average of 32% of the labeled TH cells in the ventrolateral portion of the ARC contained GRF. These findings support the hypothesis of co-expression of dopamine with GRF from the ARC.