5-羟色胺和一氧化氮合酶在大鼠中脑导水管周围灰质 和中缝核簇神经元内的共存

实验采用 NADPH组织化学和 5 - HT免疫组织化学双重显色方法研究了 5 - HT和一氧化氮合酶在大鼠中脑导水管周围灰质 (PAG)和中缝核簇神经元的分布特征及共存情况。结果表明 ;(1 )在 PAG腹外侧区中观察到大量的 NOS阳性神经元和 5 - HT样免疫阳性神经元 ,但是 NOS/ 5 - HT双标神经元较少 ,仅占该区 5 - HT样免疫阳性神经元 2 0 .1 % ,并且主要分布在该区的内侧部 ;在 PAG的背外侧区中观察到密集的 NOS阳性神经元 ,但是几乎未见 5 - HT免疫阳性神经元分布。(2 )在中缝核簇的大多数亚核内均可观察到大量的 NOS神经元和 5 - HT免疫阳性神经元。在中缝背核的内侧部、中缝背核的尾侧部、中缝正中核、尾侧线形核、中缝大核和中缝隐核内双标神经元分别占所在部位中 5 - HT免疫阳性神经元的 44 .6 %、5 3.4%、 44 .4%、 2 6 .2 %、 2 6 .7%和 2 1 .8%。然而在中缝苍白核内仅偶见少数双标神经元。研究结果表明 ,在 PAG和中缝核簇的一些神经元内 5 - HT可以与 NOS共存 ,提示这两种神经活性物质在功能上可能存在着某种相关性 ,有关这些双标神经元的功能意义尚需进一步研究。

CO-EXISTANCE OF 5-HT AND NITRIC OXIDE SYNTHASE IN THE NEURONS OF RAT MIDBRAIN PERIAQUDUCTAL GRAY AND RAPHE NUCLEAR COMPLEX

By using the method of NADPA d histochemisty combining with serotonin (5 HT) immunocyto chemistry technique, we investigated the distribution of nitric oxide synthase (NOS) and 5 HT, and the coexistence of them in the midbrain periaqueductal gray(PAG) and raphe nuclear complex of the rat. The results showed that numerous neurons in the PAG and raphe nuclear complex displayed both 5 HT like immunoreactivity (5 HT LI) and NOS positivity: (1)Within the midial portion of the PAG ventrolateral subdivision (VLS), a large number of 5 HT LI neurons and NOS positive neurons were observed, whereas about 20 1% of the 5 HT LI neurons displayed NOS positivity within the lateral portion of VLS. Dense NOS positive neurons were observed within dorsolateral subdivision of PAG. However, 5HT LI neurons were rarely seen in this subdivision. (2) In the majority of subnucleus of raphe nuclear complex, a lot of neurons were doubly labeled. Cell counts showed that about 44 6%, 53 4%,44 4%,26 2%,26 7% and 21 8% of 5 HT LI neurons displayed NOS positivity in the midial subdivision of the nucleus raphe dorsalis (DR), the caldal subdivision of DR, nucleus raphe midian, caldal subdivision of nucleus lineris and nucleus raphe magnus and nucleus raphe obcuse, respectively. However, sparse doubly labeled neurons were observed in nucleus raphe pallidus. These results suggest there are some functional correation between 5 HT and NO. The functional role of double labeled neurons remains to be further investigated.