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| 題 名 | 感壓反射功能對血壓及血管阻力管制之交互作用及重調現象 |
|---|---|
| 作 者 | 陳幸一; | 書刊名 | 醫學研究 |
| 卷 期 | 11: 附輯1 民80.04 |
| 頁 次 | 頁17-30 |
| 分類號 | 398.34 |
| 關鍵詞 | 交互作用; 血管; 血壓; 阻力; 重調現象; 感壓反射; 管制; |
| 語 文 | 中文(Chinese) |
| 中文摘要 | 本實驗室過去的研究中發現感壓反射功能在增加血量或以藥物引起Bezold-Jarisch反射時受到來自心肺接受器傳入神經之調控。在增加血量時產生感壓反射功能之變化是透過迷走神經及主動脈神經之傳入纖維所媒介,而這些傳入訊息對於感壓反射功能區線不同部位之斜率或增益值產生了不同的作用,在Bezold-Jarisch反射時透過迷走神經傳入徑,顯著減弱感壓反射之效果,在此實驗中我們闡明了感壓反射與Bezold-Jarisch反射之交互作用。 最近之實驗中觀察到感壓接受器在暴露於一新的壓力之後,迅速發生對於血壓及血管阻力控制之急性適應及重調現象。在麻醉及切除迷走神經之狗,頸動脈竇予以分離以便控制竇內壓(CSP)。進而研究感壓反射對於全身血壓(SAP)及臀腿部血管阻力之作用,臀腿部以恆定血流灌注,以其灌注壓(HPP)之改變代表血管阻力之變化,我們首先觀察CSP固定於不同水平過程中SAP及HPP之變化,然後將CSP降至40mmHg再以斜升方式增加至180-200mmHg以建立感壓反射之CSP-SAP及CSP-HPP曲線。此一系統先於100mmHg CSP之固定壓中穩定,將CSP降低至50mmHg並固定於此水平15分鐘,SAP及HPP先升高至一水平,然後逐漸下降,於5分鐘內達一穩定水平;相反方向增高CSP固定壓至150mmHg,SAP及HPP先降至一低水平,然後向上適應,並於5分鐘內達一穩定水平。以斜升CSP方式得到之CSP-SAP及CSP-HPP曲線(以logistic function分析)也因為在不同之固定壓後有所變化,感壓反射功能曲線因提高固定壓而向右移,亦即發生急性重調現象,此一現象之特性為在高固定壓時,反射之閾壓、中點壓及飽合壓值均提高,但不顯著影響反射之斜率或增益,當感壓反射在固定壓中間發生向上或向下之適應現象與反射曲線之位移以圖形分析時,我們發現急性適應與重調為感壓反射採取一種浮動性功能變化的表現,因壓力變化而調整其反射作用的範圍,而不改變其反射作用的斜率或增益。 |
| 英文摘要 | Previous studies in our laboratory demonstrated that the baroreflex functions were modulated by affect inputs from the cardiopulmonary receptors during volume expansion and Bezold-Jarisch reflex. Recent studies indicated that the arterial baroreceptor could rapidly readjust to a new pressure level and displayed acute adaptation and resetting in the control of arterial pressure and vascular resistance. In anesthetized and vagotomized dogs, the carotid sinuses were vasculary isolated to control and adjust the carotid sinus pressure (CSP). The baroreflex changes in vascular resistance and systemic arterial pressure (SAP) were studied in 10 dogs. The hindquarters region was perfused with constant flow and the changes in perfusion pressure (HPP) reflected the changes in hindquarters vascular resistance. SAP other than the perfused bed was obtained from the brachial artery. We first observed the changes in SAP and HPP during CSP holding at different levels. Thereafter, the CSP was lowered to 40 mmHg and increased to 180-200 mmHg in ramp fashion to obtain the CSP- SAP and CSP-HPP baroreflex function curves. The system was initially satbilized at a sinus holding pressure (HP) of 100 mmHg. During a 15 min HP at 50 mmHg, the SAP and HPP were initially elevated to a high level and then adapted downward to a stable level in 5 min. On the other hand, an increase of HP to 150 mmHg caused decreases in SAP and HPP to low levels and then adapted upward to quasi-steady levels in 5 min. The CSP-SAP and CSP-HPP curves constructed by logistic function analysis from the ramp protocol were also significantly affected by the HPs. The baroreflex function curves were shifted to the right at high HPs. There were significant increases in the threshold, midpoint and saturation pressures as the HP was elevated. However, the resetting was characterized by a parallel shift of the CSP-SAP and CSP-HPP curves without significant changes in the baroreflex sensitivity or gain. As the acute adaptation and restting are correlated using a graphic analysis, we hypothesize that the baroreceptors can recognize a new pressure level within minutes. The inherent ability incurs downward and upward adaptation as well as resetting at lower and higher holding pressure, respectively. |
本系統中英文摘要資訊取自各篇刊載內容。