• 作者： 陳幸一；陳樹仁；陳雪嬌
• 作者服務機構： 國防醫學院生理及生物物理學系
• 中文摘要： 利用Chloralose及Urethan麻醉之?及狗（切除迷走神經）以研究刺激腦幹對於臀腿部血管阻力及容積的作用。?之臀腿部以正常方式-可變壓力及血流-灌注，利用容積描記器以測定局部血量之變化；狗之臀腿部則以衡定血流灌注， 分別以灌注壓及靜脈出流之變化測量阻力及容積之改變。剌激腦幹之不同部位產生各種程度之血管阻力變化，但是明顯之血量容積變化僅發生於當刺激產生肌肉動作之時。以Gallamine麻痺動物之後，雖然血管阻力變化仍然明顯，血量容積之變化則不顯著。在很少次數的刺激中，發現最大的血量變化僅達局部總血量之10﹪，統計所有刺激點引起之靜脈收縮產生之血 量容積變化??公斤體重0.25±0.1毫升，作用十分輕微。對於血管阻力（主要?細動脈的反應）變化而言，刺激腦幹引起 之臀腿部細動脈收縮及弛張之點並未形成一特定集中區，而是散佈於網狀組織之中， 一般而言，背部及側部較多收縮點，而 近中線及腹部較多弛張點。在狗之臀腿部以衡定血流灌注，刺激腦幹引起之體循環血壓變化及臀腿灌注壓變化（阻力變化） 方向不一定一致，?使方向相同，在變化的大小上並不呈現直線關係。研究結果表示腦幹之交感神經機構對於臂部之阻力 性血管有明顯之管制作用，對於容積性靜脈血管之支配作用則不重要。骨骼肌之靜脈?流主要機轉可能依賴肌肉動作的壓擠作用。在腦幹中，交感神經對於全身及臀腿部循環的阻力性血管也有相當程度的分化管制作用。
• 英文摘要： The responses of resistance and capacitance vessels to electrical stimulation of the brain stem were investigated in vagotomized cats and dogs anesthetized with chloralose and urethan. The feline hindquarters were perfused normally with variable flow and pressure, and plethysmo-graph technique was utilized to monitor the change in regional blood volume. In the canine hindquarters, constant-flow perfusion was used and the resistance and capacitance responses were indicated by the change in perfusion pressure and venous outflow, respectively. Stimulation of the medulla oblongata and pons at different areas caused various changes in vascular resistance. Discernible change in vascular capacitance was observed only when stimulation evoked muscular activity. After neuromuscular blockade with gallamine, there was no appreciable capacitance response despite marked change in resistance. The maximum centrogenic capacity change seen in a few occasions was approximately 10% of the regional blood volume. The overall centrally induced venoconstriction produced only 0.25?.1 ml/kg reduction of the hindquarters volume. The distribution of constrictor and dilator points for the hindquarters resistance vessels was diffuse in the pontine and medullary reticular formation. In the dog's hindquarters under constant flow perfusion, the changes in systemic arterial pressure and hindquarters perfusion pressure were poorly correlated. The results of the present study indicate that the brain stem sympathetic vasoconstrictor system innervates the hindquarters resistance vessels, whereas central autonomic control on the limb capacitance vessels is not significant. Venous return from the skeletal muscle vasculature may be mainly dependent upon the muscular pump. In the brain stem, there exists differential sympathoadrenergic control mechanism on the resistance vessels between the systemic and hindquarters circulation.
• 中文關鍵字： --
• 英文關鍵字： --