Stine S M, Yang H Y, Costa E
J Neurochem. 1982 Apr;38(4):1144-50. doi: 10.1111/j.1471-4159.1982.tb05361.x.
Somatostatin distribution was measured quantitatively in the rat spinal cord by radioimmunoassay. Rostro-caudally, somatostatin content was about 50% higher in lumbar-sacral cord than in cervical or thoracic levels. The dorso-ventral distribution is more uneven: somatostatin is highest in the dorsal horn, where the peptide is 15 times as concentrated as it is in the ventral white matter, the region of lowest concentration. However, measurable amounts of the peptide were found in all regions studied. Dorsal root ganglionectomy decreased somatostatin levels in the dorsal cord, supporting the previously proposed role for this peptide as a primary sensory neurotransmitter or modulator; but somatostatin content also was decreased both rostral and caudal to spinal transection, indicating the presence of ascending and descending somatostatin pathways within the spinal cord. Brain levels did not change. Met-enkephalin and substance P were also measured after the above surgical manipulations. Met-enkephalin content was not altered and substance P content was lowered significantly only after ganglionectomy. Although this study confirms the primary sensory neuron as the origin of a part of spinal cord somatostatin, it further indicates the presence of ascending and descending somatostatin pathways within the rat spinal cord.
采用放射免疫分析法对大鼠脊髓中的生长抑素分布进行了定量测定。从颅尾方向来看，腰骶段脊髓中的生长抑素含量比颈段或胸段高约50%。背腹侧分布更不均匀：生长抑素在背角中含量最高，该区域的肽浓度是腹侧白质（浓度最低的区域）的15倍。然而，在所有研究区域均发现了可测量量的该肽。背根神经节切除术降低了脊髓背侧的生长抑素水平，支持了之前提出的该肽作为初级感觉神经递质或调节剂的作用；但脊髓横断术前后，生长抑素含量在头端和尾端均降低，表明脊髓内存在生长抑素的上行和下行通路。脑内水平未发生变化。在上述手术操作后还对甲硫氨酸脑啡肽和P物质进行了测定。甲硫氨酸脑啡肽含量未改变，仅在神经节切除术后P物质含量显著降低。尽管本研究证实了初级感觉神经元是脊髓中部分生长抑素的起源，但它进一步表明大鼠脊髓内存在生长抑素的上行和下行通路。
