Ditirro F J, Ho R H, Martin G F
J Comp Neurol. 1981 May 10;198(2):351-63. doi: 10.1002/cne.901980212.
The occurrence and distribution of substance-P (SP), somatostatin (SOM), and enkephalin (ENK) were studied in the North American opossum, a generalized marsupial. Substance-P immunoreactivity was present in the tract of Lissauer as well as within lamina I, the outer part of lamina II, the lateral portion of laminae III through VII, and lamina X at all spinal levels. Although present, it was very spare in the ventral horn. Substance-P was also localized within autonomic areas of the thoracolumbar cord. ENK immunoreactivity was present in laminae I-III and laminae VII-X, as well as within autonomic areas. There was more ENK immunoreactivity in the ventral horn than SP. The densest aggregates of ENK, however, were found within the outer part of lamina II. In contrast, SOM could not be localized within the spinal cord of the opossum. (See NOTE ADDED IN PROOF).
对北美负鼠（一种广义的有袋动物）中P物质（SP）、生长抑素（SOM）和脑啡肽（ENK）的分布情况进行了研究。P物质免疫反应性存在于脊髓背外侧束以及所有脊髓节段的Ⅰ层、Ⅱ层外侧部、Ⅲ至Ⅶ层外侧部分和Ⅹ层。虽然存在，但在腹角中含量极少。P物质也定位于胸腰段脊髓的自主神经区域。脑啡肽免疫反应性存在于Ⅰ至Ⅲ层、Ⅶ至Ⅹ层以及自主神经区域。腹角中的脑啡肽免疫反应性比P物质更多。然而，脑啡肽最密集的聚集区位于Ⅱ层外侧部。相比之下，在负鼠的脊髓中未发现生长抑素。（见校样新增注释）
