在体和离体的鸡背根节神经细胞5-羟色胺的免疫组织化学研究

用PAP免疫组织化学方法研究了鸡胚和雏鸡背根节内5-HT神经细胞的形态与胚胎发育,并在离体细胞培养条件下研究了靶周围组织(皮肤)对其胚胎发育的影响。在鸡腰骶部背根节,5-HT免疫反应阳性细胞最先出现于鸡胚13d(E_(13)),占0.4%;孵出后2d(AH_2)占6.2%。阳性细胞主要为大的A类细胞和极少的小B类细胞。免疫反应阳性的周围神经末梢位于皮肤和跟腱中。取自E_9鸡胚的背根节细胞培养7d后有部分出现5-HT阳性免疫反应,取自E_6鸡胚的背根节细胞培养10d仍为阴性反应;然而,当取自E_6鸡胚的背根节细胞与皮肤组织联合培养10d后,则出现5-HT阳性免疫反应细胞。本文还对脊髓5-HT细胞的出现进行了讨论。

EXPRESSTION OF SEROTONIN IMMUNOREACTIVITY BY CHICK DORSAL ROOT GANGLION NEURONS IN VIVO AND IN VITRO

The expression of serotonin by primary sensory neurons as well as their central and peripheral projections were studied in the chick dorsal root ganglion and their related target tissues by a sensitive immunocytochemistry in vivo and in vitro. Within the chick lumbo-sacreal dorsal root ganglion cells, serotonin immunoreactivity is first expressed in 0.4% at E_(13) and reaches a percentage of 6.2 at AH_2. The majority of serotonin immunoreactive cells were related to the large A cells and a few small B cells. Their peripheral axons projected to the tendon and skin tissues. The central axons projected to the dorsal horn of spinal cord and concetrated in lamina I and II. The DRG cells cultured from chick embryo 9 days(E_9), after the formation of sensory connections with their peripheral targets shown some sensory neurons were immunostained by serotonin antiserum respectivily after 7 days of culture. However, the DRG cells cultured from E_6, prior to formation of specific connection with peripheral target tissues were devoid of any serotonin immunoreactive neurons after 10 days of culture. Moreover, when the E_6 DRG cells co-cultured with skin tissues for 10 days, some of the DRG cells were immunostained by serotonin antiserum, and the terminal fibers of sensory neurons were observed occasionaly. In conclusion, the initiation of serotonin expression by cultured chick DRG cells seems to be depended on skin peripheral target factors.