Maekawa F, Tsukahara S, Tanaka K, Ohki-Hamazaki H
Department of Life Science, Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan.
Neuroscience. 2004;125(3):569-82. doi: 10.1016/j.neuroscience.2004.01.057.
Bombesin (BN)-like peptide receptors are known to be essential to the regulation of not only homeostasis, including feeding behavior, but also of emotional systems in mammal. Recently, two novel BN receptors, chicken BN-like peptide receptor subtype-3.5 (chBRS-3.5) and gastrin-releasing peptide receptor (chGRP-R), have been identified. Here, we report the localizations of these receptors' mRNAs in the chick brain through development using in situ hybridization. First, chBRS-3.5 mRNA signals were found in the dorsal ventricular ridge at embryonic day (ED) 9. Strong signals were observed in the hyperpallium accessorium, nidopallium and nucleus basorostralis pallii, and moderate signals were found in the hippocampus, cortex piriformis, hyperpallium intercalatum, area temporo-parieto-occipitalis, nucleus striae terminalis lateralis, nucleus olfactorius anterior and organum septi lateralis at ED16. This wide expression in the pallium persisted during posthatch periods. Abundant expressions in the hyperpallium, nidopallium, considered to be similar to the mammalian cortex, as well as in the hippocampus, indicate participation of these molecules in the processing of sensory information, motor function, learning and memory. Telencephalic areas devoid of chBRS-3.5 signals were the entopallium, arcopallium anterius, globus pallidus, nucleus intrapeduncularis, tuberculum olfactorius, nucleus septalis lateralis, hypothalamic and thalamic areas. In contrast to chBRS-3.5, chGRP-R mRNA signals were found in the pallidum at ED5 and 9. At ED16, chGRP-R mRNA signals were localized in the medial striatum and hypothalamus. GRP-R expression in the hypothalamic region was phylogenically conserved. Thus, chBRS-3.5 mRNA signals were distributed in a broader region and were more intense than chGRP-R mRNA. Taken together, chGRP-R and chBRS-3.5 mRNA occurred in similar regions of mammals that express GRP-R. BN/GRP-immunoreactive neurons and varicosities were found mainly in the pallium, especially in the hyperpallium accessorium and nidopallium, and this distribution coincided with that of chBRS-3.5 mRNA. This result suggests that the endogenous ligands for chBRS-3.5 were likely BN-like peptides produced in the pallium.
蛙皮素（BN）样肽受体不仅对包括进食行为在内的体内平衡调节至关重要，对哺乳动物的情绪系统调节也很关键。最近，已鉴定出两种新型BN受体，即鸡BN样肽受体亚型-3.5（chBRS-3.5）和胃泌素释放肽受体（chGRP-R）。在此，我们通过原位杂交技术报告了这些受体的mRNA在雏鸡大脑发育过程中的定位情况。首先，在胚胎第9天（ED9），chBRS-3.5 mRNA信号出现在背侧脑室嵴。在副高皮质、巢皮质和基底嘴侧苍白球核中观察到强信号，在海马体、梨状皮质、插入高皮质、颞顶枕叶区域、外侧终纹核、前嗅核和外侧隔器官中发现中等信号。这种在皮质中的广泛表达在孵化后阶段持续存在。在被认为类似于哺乳动物皮质的副高皮质、巢皮质以及海马体中的丰富表达，表明这些分子参与了感觉信息处理、运动功能、学习和记忆过程。没有chBRS-3.5信号的端脑区域有内皮质、前弓状皮质、苍白球、脚内核、嗅结节、外侧隔核、下丘脑和丘脑区域。与chBRS-3.5不同，chGRP-R mRNA信号在ED5和ED9时出现在苍白球中。在ED16时，chGRP-R mRNA信号定位于内侧纹状体和下丘脑。GRP-R在下丘脑区域的表达在系统发育上是保守的。因此，chBRS-3.5 mRNA信号分布在更广泛的区域，且比chGRP-R mRNA信号更强。综上所述，chGRP-R和chBRS-3.5 mRNA出现在表达GRP-R的哺乳动物的相似区域。BN/GRP免疫反应性神经元和曲张体主要存在于皮质中，尤其是在副高皮质和巢皮质中，这种分布与chBRS-3.5 mRNA的分布一致。这一结果表明，chBRS-3.5的内源性配体可能是在皮质中产生的BN样肽。
