Kanayama H, Yasuhara O, Matsuo A, Tooyama I, Aimi Y, Bellier J-P, Nagy J I, Fukui K, Kimura H
Molecular Neuroscience Research Center, Shiga University of Medical Science, Seta Tsukinowa-cho, Otsu, 520-2192, Shiga, Japan.
Neuroscience. 2003;118(1):243-51. doi: 10.1016/s0306-4522(02)00868-0.
A splice variant of choline acetyltransferase mRNA has recently been identified in the pterygopalatine ganglion of rat. An antibody against this variant protein (designated pChAT) was demonstrated to immunolabel peripheral cholinergic neurons. In the present study, we investigated the expression of pChAT in rat brain. Amongst the brain regions examined, magnocellular neurons in the tuberomammillary nucleus of the posterior hypothalamus were immunohistochemically labelled with anti-pChAT antibody, whilst no immunolabelling was detected in cholinergic neurons in the basal forebrain or striatum. RT-PCR analysis confirmed the expression of pChAT mRNA in the posterior hypothalamus. The distribution of pChAT-positive neurons in the tuberomammillary nucleus was compared with that of neurons positive for adenosine deaminase, which is contained in all neurons of this nucleus. After colchicine treatment to inhibit axonal transport of enzyme, virtually all pChAT-positive cells contained adenosine deaminase. Conversely, about 85% of adenosine deaminase-positive cells contained pChAT in the ventral area, whilst 19% of adenosine deaminase-positive cells were pChAT-positive in the dorsal area. Long axonal projections of pChAT-positive cells in the tuberomammillary nucleus were shown by retrograde labelling of these cells after injection of cholera-toxin B subunit into the cerebral cortex. This study demonstrates that a splice variant of choline acetyltransferase is expressed in the tuberomammillary nucleus of rat. The results raise the possibility that some of the known diverse projection areas of this nucleus may have a cholinergic component.
最近在大鼠翼腭神经节中发现了胆碱乙酰转移酶mRNA的一种剪接变体。已证实一种针对该变体蛋白（命名为pChAT）的抗体可对周围胆碱能神经元进行免疫标记。在本研究中，我们调查了pChAT在大鼠脑中的表达。在所检查的脑区中，下丘脑后部乳头体核中的大细胞神经元被抗pChAT抗体免疫标记，而在基底前脑或纹状体的胆碱能神经元中未检测到免疫标记。逆转录聚合酶链反应（RT-PCR）分析证实了pChAT mRNA在下丘脑后部的表达。将乳头体核中pChAT阳性神经元的分布与该核所有神经元中所含的腺苷脱氨酶阳性神经元的分布进行了比较。在用秋水仙碱处理以抑制酶的轴突运输后，几乎所有pChAT阳性细胞都含有腺苷脱氨酶。相反，在腹侧区域约85%的腺苷脱氨酶阳性细胞含有pChAT，而在背侧区域19%的腺苷脱氨酶阳性细胞为pChAT阳性。将霍乱毒素B亚基注射到大脑皮层后，通过对乳头体核中pChAT阳性细胞进行逆行标记，显示了这些细胞的长轴突投射。本研究表明，胆碱乙酰转移酶的一种剪接变体在大鼠乳头体核中表达。这些结果增加了该核一些已知的不同投射区域可能具有胆碱能成分的可能性。
