Cardiac output in Xenopus laevis tadpoles during development and in response to an adenosine agonist.
Cardiac output in Xenopus laevis tadpoles during development and in response to an adenosine agonist.
复制标题
非洲爪蟾蝌蚪在发育过程中以及对腺苷激动剂的反应中的心输出量。
DOI：
10.1152/ajpregu.1996.270.5.r997
复制
发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Rovainen,CM
中科院分区：
文献类型：
--
作者：
Tang,YY;Rovainen,CM
我们测试的假设，心脏和动脉扩大心输出量（CO）增加的发展和容量超负荷。将43 - 50期的非洲爪蟾的透明白化病蝌蚪在0.3 - 0.5 mM苯并咪唑中麻醉。在心动周期期间，在数字化视频帧中测量心室的面积和半径[最大和最小半径（分别为Rmax和Rmin）]。根据Rmax和Rmin计算每搏输出量（SV）和CO。在主动脉弓中测量3.4微米荧光珠的最大速度。用Landis法估计动脉压。在正常发育过程中，心室半径和主动脉弓直径随着蝌蚪的长度而增加，SV（0.7 μ L/g）和CO（70 μ L·g-1·min-1）随着湿重而增加。容量超负荷是由血管舒张腺苷激动剂5'-N-乙基羧酰胺腺苷（NECA）在水族馆水中诱导的。急性（0.5 - 4小时）NECA显著增加Rmax和心率。慢性（> 1周）NECA显著增加Rmax和Rmin。SV和CO增加2倍以上，血压降低，比血管电导增加5倍以上。它的结论是，NECA通过增加填充和加速生长的组合增加了爪蟾蝌蚪中的CO。
We test the hypothesis that the heart and arteries enlarge with increased cardiac output (CO) during development and volume overload. Transparent albino tadpoles of Xenopus laevis at stages 43-50 were anesthetized in 0.3-0.5 mM benzocaine. Areas and radii [maximum and minimum radius (Rmax and Rmin, respectively)] of the ventricle were measured in digitized video frames during the cardiac cycle. Stroke volume (SV) and CO were calculated from Rmax and Rmin. Maximal velocities of 3.4-microns fluorescent beads were measured in the aortic arches. Arterial pressure was estimated by the Landis method. During normal development, the radii of the ventricle and aortic arch diameters increased with lengths of tadpoles, and SV (0.7 microliters/g) and CO (70 microliters.g-1.min-1) with wet weights. Volume overload was induced by a vasodilatory adenosine agonist 5'-N-ethylcarboxamidoadenosine (NECA) in the aquarium water. Acute (0.5-4 h) NECA significantly increased Rmax and heart rate. Chronic (> 1 wk) NECA significantly increased both Rmax and Rmin. SV and CO increased more than two times, blood pressures decreased, and specific vascular conductances increased more than five times. It is concluded that NECA increases CO in Xenopus tadpoles through a combination of increased filling and accelerated growth.