貓延腦縫合核心臟血管調節機構之定位

Abstract

以氯醛醣及?酯混合劑麻醉的貓，用來研究延腦縫合核區心臟血管調節機構的分佈位置。電刺激延腦縫合核，除了引起心跳、血壓的改變，也造成局部區域血流量的改變，特定部位的縫合核對特定的血管舒縮功能有特別強的控制力。這些心臟血管反應主要是經由交感神經傳出衝動至周邊的心臟血管系統而引發。腦內血壓胺在利用對氯苯丙胺酸處理減少了90﹪以後，延腦縫合核內能產生刺激反應的區域擴大，而且刺激時所產生之血壓的升降程度亦增強，因此延腦中血壓胺神經元可能扮演著調節血壓的角色，使血壓維持恆定。

The topographic organization of the medullary raphe nuclei (MRN) in controlling cardiovascular functions was studied in chloralose-urethane anesthetized cats. Electrical stimulation within the MRN elicited cardiovascular responses which included increases and decreases of heart rate and blood pressure, and changes of resistances in various regional circulatory beds. The MRN could be devided into seven regions according to the types of circulatory responses they produced. The stimulus-produced cardiovascular responses were only slightly affected by bilateral vagotomy, indicating the MRN controls cardiovascular functions primarily through sympathetic outputs. After depleting 90% serotonin in the central nervous system by pretreating the animals with p-chlorophenylalanine for three days, electrical stimulation of the MRN was more effective in changing the blood pressure. The magnitude of pressor and depressor effects increased, and the cardiovascular active zones in the MRN expanded. Therefore, serotonin may play a role in maintaining blood pressure at its normal level.