Hensler J G, Ferry R C, Labow D M, Kovachich G B, Frazer A
Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia.
Synapse. 1994 May;17(1):1-15. doi: 10.1002/syn.890170102.
The binding of 3H-CN-IMI to 5-HT uptake sites, as measured by quantitative autoradiography, was used as a marker of serotonergic neurons. Within the dorsal raphe nucleus the binding of 3H-CN-IMI was compared in adjacent coronal sections of rat brain to the binding of 3H-DPAT to 5-HT1A receptors, which have a known somatodendritic localization. The heterogeneous pattern of binding of these two radioligands within the dorsal raphe nucleus was similar and corresponded to the distribution of serotonergic cell bodies as visualized by 5-HT immunohistochemistry. Intracerebroventricular administration of 5,7-dihydroxytryptamine (5,7-DHT), which caused a dramatic loss of 5-HT immunoreactivity and 3H-DPAT binding to 5-HT1A receptors, resulted in a marked reduction of 3H-CN-IMI binding in this nucleus. Treatment of rats with a dose of para-chloroamphetamine (PCA) which has been reported to selectively lesion serotonergic processes arising from the dorsal raphe nucleus, while sparing serotonergic cell bodies and projections from the median raphe nucleus, did not alter the binding of 3H-DPAT or 3H-CN-IMI in the dorsal raphe nucleus; serotonergic cell bodies appeared morphologically unaffected. The lack of effect of PCA treatment on the binding of 3H-DPAT and 3H-CN-IMI is consistent with a somatodendritic localization of the 5-HT transporter in the dorsal raphe nucleus. PCA treatment appeared to produce a moderate loss of serotonergic innervation in serotonergic terminal field areas as visualized by serotonin immunohistochemistry. The reductions in 3H-CN-IMI binding observed in terminal field areas (24 to 69%) following treatment of rats with PCA did not reflect a marked differential innervation of forebrain areas by the dorsal and medial raphe nuclei as expected from previous biochemical studies, and were not entirely consistent with the findings of neuroanatomical studies using histochemical techniques. Site-specific injection of 5,7-DHT into the dorsal raphe nucleus produced an 80 +/- 11% reduction in the binding of 3H-CN-IMI in this nucleus, whereas the binding of 3H-CN-IMI in the median raphe nucleus was not reduced.(ABSTRACT TRUNCATED AT 400 WORDS)
通过定量放射自显影法测定的3H-CN-IMI与5-羟色胺（5-HT）摄取位点的结合，被用作血清素能神经元的标志物。在大鼠脑的相邻冠状切片中，比较了中缝背核内3H-CN-IMI的结合与3H-DPAT与5-HT1A受体的结合情况，5-HT1A受体具有已知的胞体树突定位。这两种放射性配体在中缝背核内的结合异质性模式相似，且与5-HT免疫组织化学显示的血清素能细胞体分布相对应。脑室内注射5,7-二羟基色胺（5,7-DHT），导致5-HT免疫反应性和3H-DPAT与5-HT1A受体的结合显著丧失，使该核内3H-CN-IMI的结合明显减少。用据报道可选择性损伤源自中缝背核的血清素能神经纤维而保留中缝正中核的血清素能细胞体和投射的对氯苯丙胺（PCA）剂量处理大鼠，并未改变中缝背核内3H-DPAT或3H-CN-IMI的结合；血清素能细胞体在形态上似乎未受影响。PCA处理对3H-DPAT和3H-CN-IMI结合缺乏影响，这与中缝背核中5-HT转运体的胞体树突定位一致。PCA处理似乎使血清素能终末场区域的血清素能神经支配出现中度丧失，这通过血清素免疫组织化学可见。在用PCA处理大鼠后，终末场区域观察到的3H-CN-IMI结合减少（24%至69%），并不反映如先前生化研究预期的中缝背核和中缝内侧核对前脑区域的明显不同神经支配，且与使用组织化学技术的神经解剖学研究结果不完全一致。向中缝背核进行位点特异性注射5,7-DHT，使该核内3H-CN-IMI的结合减少80±11%，而中缝正中核内3H-CN-IMI的结合未减少。（摘要截断于400字）
