Angel I, Janowsky A, Paul S M
Clinical Neuroscience Branch, NIMH, Bethesda, MD 20892.
Brain Res. 1989 Dec 4;503(2):339-41. doi: 10.1016/0006-8993(89)91687-9.
The effects of intracerebroventricular administration of 6-hydroxydopamine (6-OHDA) and 5,7-dihydroxytryptamine (5,7-DHT) on sodium-sensitive [3H]mazindol binding were investigated in the rat hypothalamus and corpus striatum. In the hypothalamus, specific [3H]mazindol binding was inhibited by low concentrations of sodium and stimulated by high-sodium concentrations, whereas in the corpus striatum, only a sodium-dependent stimulation of [3H]mazindol binding was observed. Lesions with 6-OHDA significantly reduced sodium-dependent [3H]mazindol binding in the corpus striatum, but had no effect on the binding of [3H]mazindol in the absence of sodium. Lesions of serotonergic neurons with 5,7-DHT, however, had no effect on [3H]mazindol binding in the striatum, but resulted in a significant increase in the number of [3H]mazindol binding sites in the hypothalamus. These data suggest that [3H]mazindol may bind to two anatomically distinct binding sites, one that is stimulated and the other inhibited by sodium. The sodium-stimulated binding sites appear to be located on dopaminergic terminals in the striatum, and in the hypothalamus, the sodium-inhibited sites appear to be regulated by serotonergic neuronal activity.
研究了脑室内注射6-羟基多巴胺（6-OHDA）和5,7-二羟基色胺（5,7-DHT）对大鼠下丘脑和纹状体中钠敏感性[3H]吗吲哚结合的影响。在下丘脑中，低浓度钠抑制特异性[3H]吗吲哚结合，高钠浓度则刺激该结合；而在纹状体中，仅观察到[3H]吗吲哚结合的钠依赖性刺激。6-OHDA损伤显著降低纹状体中钠依赖性[3H]吗吲哚结合，但对无钠情况下的[3H]吗吲哚结合无影响。然而，5,7-DHT对血清素能神经元的损伤对纹状体中[3H]吗吲哚结合无影响，但导致下丘脑中[3H]吗吲哚结合位点数量显著增加。这些数据表明，[3H]吗吲哚可能结合于两个解剖学上不同的结合位点，一个受钠刺激，另一个受钠抑制。钠刺激的结合位点似乎位于纹状体中的多巴胺能终末，而在下丘脑中，钠抑制的位点似乎受血清素能神经元活动调节。
