Liu R P, Swenberg M L
Department of Anatomy and Cell Biology, Georgetown University, Washington, DC.
Brain Res. 1988 Dec 13;475(1):73-9. doi: 10.1016/0006-8993(88)90200-4.
The autoradiographic localization of substance P (SP) binding sites and the distribution of SP immunoreactive (SP-ir) neurons in the periaqueductal gray (PAG) of the rat were studied. The autoradiograms revealed an uneven distribution of specific SP binding sites in the PAG. Throughout the rostrocaudal extent, the densest ligand binding sites were observed in the medial PAG adjacent to the aqueduct, and extended into the dorsal medullary region and to the dorsal raphe nucleus midline region. The distribution of binding sites were denser in the dorsal PAG than the ventral half. In the cuneiform nucleus, a lesser and a denser binding site were observed in the medial and lateral halves respectively. Optical density readings of autoradiograms also supported the differences between these areas. The distribution of SP-ir neurons was also found uneven. In the rostral PAG, SP-ir neurons were found in the entire dorsoventral region. In the caudal PAG, SP-ir neurons were found as 3 clusters: in the dorsomedial, dorsolateral and ventrolateral regions. The present study revealed more SP-ir neurons in the PAG than previously reported.
研究了大鼠中脑导水管周围灰质（PAG）中P物质（SP）结合位点的放射自显影定位及SP免疫反应性（SP-ir）神经元的分布。放射自显影片显示PAG中特异性SP结合位点分布不均。在整个前后范围内，在与导水管相邻的内侧PAG中观察到最密集的配体结合位点，并延伸至背侧延髓区域和中缝背核中线区域。背侧PAG中的结合位点分布比腹侧半部更密集。在楔形核中，在内侧半部和外侧半部分别观察到较少和较密集的结合位点。放射自显影片的光密度读数也支持这些区域之间的差异。还发现SP-ir神经元的分布不均。在嘴侧PAG中，在整个背腹区域均发现了SP-ir神经元。在尾侧PAG中，SP-ir神经元分为3簇：位于背内侧、背外侧和腹外侧区域。本研究显示PAG中的SP-ir神经元比以前报道的更多。
