Bessho Yuki, Iwakoshi-Ukena Eiko, Tachibana Tetsuya, Maejima Sho, Taniuchi Shusuke, Masuda Keiko, Shikano Kenshiro, Kondo Kunihiro, Furumitsu Megumi, Ukena Kazuyoshi
Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan.
Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama 790-8566, Japan.
Neurosci Lett. 2014 Aug 22;578:106-10. doi: 10.1016/j.neulet.2014.06.048. Epub 2014 Jun 30.
In mammals, it is established that histamine is a neurotransmitter and/or neuromodulator in the central nervous system. It is produced by the enzyme histidine decarboxylase (HDC) in the tuberomammillary nucleus of the posterior hypothalamus. However, HDC as well as histaminergic neurons have not yet been characterized in the avian brain. We have cloned the cDNA for HDC from the chicken hypothalamus and demonstrated that the chicken HDC sequence is highly homologous to the mammalian counterpart, and that the expressed protein shows high enzymatic activity. The expression of HDC mRNA at various sites in the brain was investigated using quantitative RT-PCR. The results showed that the HDC mRNA was highly expressed in the hypothalamic infundibulum. In situ hybridization analyses revealed that the cells containing HDC mRNA were localized in the medial mammillary nucleus of the hypothalamic infundibulum. Intracerebroventricular injection of histamine in chicks resulted in inhibition of feeding behavior. This is the first report of the characterization of histaminergic neurons in the avian brain, and our findings indicate that neuronal histamine exerts anorexigenic effects in chicks.
在哺乳动物中，已确定组胺是中枢神经系统中的一种神经递质和/或神经调质。它由下丘脑后部乳头体核中的组氨酸脱羧酶（HDC）产生。然而，HDC以及组胺能神经元在鸟类大脑中尚未得到表征。我们从鸡下丘脑克隆了HDC的cDNA，并证明鸡HDC序列与哺乳动物的对应序列高度同源，且表达的蛋白质具有高酶活性。使用定量RT-PCR研究了HDC mRNA在大脑各个部位的表达。结果表明，HDC mRNA在下丘脑漏斗中高度表达。原位杂交分析显示，含有HDC mRNA的细胞位于下丘脑漏斗的内侧乳头体核中。向雏鸡脑室内注射组胺会导致摄食行为受到抑制。这是关于鸟类大脑中组胺能神经元表征的首次报道，我们的研究结果表明，神经元组胺对雏鸡具有厌食作用。
