Brodin E, Linderoth B, Goiny M, Yamamoto Y, Gazelius B, Millhorn D E, Hökfelt T, Ungerstedt U
Department of Pharmacology, Karolinska Institute, Stockholm, Sweden.
Brain Res. 1990 Dec 10;535(2):227-36. doi: 10.1016/0006-8993(90)91605-g.
Extracellular levels of serotonin (5-hydroxytryptamine; 5-HT) were monitored by microdialysis in the dorsal vagal complex (DVC) and the ventral horn of the spinal cord at the level of the phrenic motor nucleus in decerebrated cats. A selective serotonin uptake inhibitor, alaproclate (10(-4) M) was included in the dialysis probe perfusion fluid to increase basal and stimulated levels of 5-HT. Electrical stimulation (30 Hz, 10 V, 0.5 ms) in the nucleus raphe obscurus, containing neurons projecting to the DVC and to the ventral horn, induced a 2-3-fold increase of the 5-HT release in both these regions. After termination of the stimulation, the release gradually decreased during the following 60 min. Substance P, which coexists with 5-HT in descending neurons, did not significantly affect the 5-HT release when it was added (100 microM) to the probe perfusion fluid. The present findings are in accordance with the hypothesis that prolonged release of 5-HT is responsible for the previously demonstrated long-lasting facilitation of phrenic activity following raphe obscurus stimulation.
在去大脑猫的背侧迷走神经复合体（DVC）和膈运动核水平的脊髓腹角，通过微透析监测细胞外5-羟色胺（5-羟色胺；5-HT）水平。透析探针灌注液中加入选择性5-羟色胺摄取抑制剂阿普氯铵（10⁻⁴ M），以提高5-HT的基础水平和刺激水平。在中缝隐核进行电刺激（30 Hz，10 V，0.5 ms），该核含有投射到DVC和腹角的神经元，可使这两个区域的5-HT释放增加2至3倍。刺激终止后，在接下来的60分钟内释放逐渐减少。与5-羟色胺共存于下行神经元中的P物质，当加入（100 μM）到探针灌注液中时，对5-羟色胺释放没有显著影响。目前的研究结果与以下假设一致，即5-羟色胺的长时间释放是先前证明的中缝隐核刺激后膈活动的持久促进作用的原因。
