Hrabovszky E, Liposits Z
Department of Anatomy, University Medical School, Pécs, Hungary.
Brain Res. 1994 Jul 25;652(1):49-55. doi: 10.1016/0006-8993(94)90315-8.
Prolactin (PRL) secretion by the anterior pituitary gland is dependent upon the tonic inhibitory influence of the tuberoinfundibular dopaminergic (TIDA) neuronal system. TIDA neurons, in turn, are regulated by various afferent neuronal systems. To support the concept that the recently-discovered neuropeptide, galanin (GAL), is one of the neurotransmitter/neuromodulator substances which might synaptically regulate the function of the TIDA system, immunocytochemical double-labeling studies were carried out in the hypothalamic arcuate nucleus (AN) of the male rat. The analysis of light microscopic preparations revealed the overlapping of GALergic and dopaminergic (detected by tyrosine hydroxylase immunoreactivity) neuronal elements in both the dorsomedial and ventrolateral parts of the AN. TH-containing perikarya and dendrites were contacted by varicose GAL-IR axons in these regions. The electron microscopic studies of ultrathin sections demonstrated axosomatic and axodendritic synapses between GALergic axons and TH-IR neurons. These findings support the view that GAL may modulate PRL release, acting as a neurotransmitter/neuromodulator in synaptic afferents to the TIDA system.
垂体前叶分泌催乳素（PRL）依赖于结节漏斗多巴胺能（TIDA）神经元系统的紧张性抑制作用。反过来，TIDA神经元受各种传入神经元系统的调节。为了支持最近发现的神经肽甘丙肽（GAL）是可能通过突触调节TIDA系统功能的神经递质/神经调质物质之一这一概念，对雄性大鼠下丘脑弓状核（AN）进行了免疫细胞化学双标记研究。光学显微镜标本分析显示，在AN的背内侧和腹外侧部分，甘丙肽能和多巴胺能（通过酪氨酸羟化酶免疫反应性检测）神经元成分相互重叠。在这些区域，含TH的胞体和树突与曲张的GAL免疫反应性轴突相接触。超薄切片的电子显微镜研究显示，甘丙肽能轴突与TH免疫反应性神经元之间存在轴体和轴树突触。这些发现支持这样一种观点，即GAL可能作为TIDA系统突触传入中的神经递质/神经调质来调节PRL释放。
