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近年来的研究表明哺乳动物的垂体前叶接受SP、CGRP等肽能神经支配。免疫电镜研究发现 ,在SP、CGRP阳性末梢中 ,除了含有阳性的大致密芯囊泡外 ,还含有大量的清亮小泡 ,提示经典递质的存在 ,其性质目前尚不清楚。GABA参与垂体前叶腺细胞分泌活动的调节 ,是可能的递质候选者之一。应用免疫组化技术发现 ,在大鼠垂体前叶两翼的外侧部及浅表部位 ,分布有GABA免疫阳性末梢。应用包埋前免疫电镜技术 ,发现 85%的GABA免疫阳性末梢与前叶腺细胞直接接触 ,由多到少依次为生长激素细胞、泌乳素细胞和促肾上腺皮质激素细胞 ,并且与上述细胞形成典型的突触结构。GABA免疫阳性末梢与生长激素细胞形成非对称型突触结构 ,与促肾上腺皮质激素细胞形成对称型突触结构 ,而与泌乳素细胞间则既有对称型突触结构 ,又有非对称型突触结构。GABA免疫阳性末梢极少与促性腺激素细胞接触。结果表明大鼠垂体前叶接受GABA能神经纤维的支配 ,GABA能末梢可直接调控垂体前叶腺细胞的分泌。大鼠垂体前叶GABA能纤维的来源则有待进一步研究
In recent years, studies have shown that mammalian pituitary receiving SP, CGRP and other peptides can be innervated. Immunoelectron microscopy found that in addition to the positive, densely packed, dense vesicles, a large number of clear vesicles were found in SP and CGRP-positive endings, suggesting the existence of classical neurotransmitters and its nature is not yet clear. GABA is involved in the regulation of glandular cell secretory activity in the anterior pituitary gland, which is one of the possible neurotransmitter candidates. Immunohistochemistry showed that GABA immunopositive terminals were distributed in the lateral and superficial parts of the anterior pituitary of rats. Using pre-embay immunoelectron microscopy, 85% of GABA immunopositive terminals were found to be in direct contact with the anterior glandular cells, with growth hormone, prolactin, and adrenocorticotrophic hormone cells in descending order and typical Synaptic structure. GABA immunopositive terminals form asymmetric synaptic structures with growth hormone cells and form symmetrical synaptic structures with adrenocorticotropic hormone cells, whereas both symmetrical synaptic structures with prolactin cells and asymmetric processes Touch structure. GABA immunopositive terminals are rarely contacted with gonadotrophs. The results showed that the anterior pituitary of rats received GABAergic nerve fibers, GABAergic terminals could directly regulate the secretion of glandular cells in the anterior pituitary gland. The origin of rat anterior pituitary GABA fibers remains to be further studied