CARDIAC-FUNCTION AND METABOLISM DURING CHOLINERGIC STIMULATION IN NEWBORN LAMB
CARDIAC-FUNCTION AND METABOLISM DURING CHOLINERGIC STIMULATION IN NEWBORN LAMB
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DOI：
10.1152/ajpheart.1977.233.4.h451
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发表时间：
1977-01-01
影响因子：
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通讯作者：
TAYLOR, JFN
中科院分区：
文献类型：
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作者：
DOWNING, SE;LEE, JC;TAYLOR, JFN
本研究旨在探讨胆碱能刺激对新生儿冠状动脉血流（CF）、氧代谢（MVO 2）和左心室收缩力（MC）的影响。用戊巴比妥（20 mg/kg）麻醉19只1-7日龄羔羊，并准备连续测量CF、心率（HR）、主动脉（AP）和左心室舒张末期（LVEDP）压力、dP/dt max和心输出量（CO）。HR、AP和CO可以根据需要进行控制。同时分析动脉和鼻窦血液样本的O2含量、红细胞压积、pH、PO 2和PCO 2。计算LV MVO 2和%O2提取（Ext）。乙酰胆碱（ACh）30-50 μ g/min·kg可使LVEDP（4cmH_2 O）增加，但dP/dt_（max）和HR无明显变化，而AP和CO不变，CF增加44%，而每搏MVO_2不变。在恒定HR（起搏）下观察到类似变化。右或左迷走神经的Suramaximal传出刺激产生心动过缓（77-68次/分钟），但收缩力、CF、Ext或MVO 2无显著变化。这些发现未被β受体阻滞剂改变。阿托品可阻断ACh灌注或迷走神经刺激引起的上述变化。它的结论是，虽然胆碱能敏感性可以证明，迷走神经刺激并不重要影响MC，CF，或MVO 2在羔羊。这可能与肾上腺素能系统发育不完全有关。
This study was designed to assess the influences of cholinergic stimulation on coronary flow (CF), oxygen metabolism (MVO2) and contractility (MC) of the left ventricle in the newborn. Nineteen lambs, 1-7 days of age, were anesthetized with pentobarbital (20 mg/kg) and prepared for continuous measurement of CF, heart rate (HR), aortic (AP) and left ventricular end-diastolic (LVEDP) pressures, dP/dt max, and cardiac output (CO). HR, AP, and CO could be controlled as desired. Simultaneous arterial and sinus blood samples were analyzed for O2 content, hematocrit, pH, PO2, and PCO2. LV MVO2 and %O2 extraction (Ext) were calculated. Acetylcholine (ACh) infusion (30-50 microgram/min-kg) caused an increase of LVEDP (4 cmH2O), but no significant change in dP/dt max or HR with constant AP and CO. CF increased by 44%, but MVO2 per beat was unchanged. Similar changes were observed with constant HR (pace). Suramaximal efferent stimulation of right or left vagus nerves produced bradycardia (77-68 beats/min) but no significant changes in contractility, CF, Ext, or MVO2. These findings were unaltered by beta blockade. The changes elicited by ACh infusion or vagal stimulation were abolished by giving atropine. It is concluded that although cholinergic sensitivity can be demonstrated, vagal stimulation does not importantly influence MC, CF, or MVO2 in the lamb. This may relate to incomplete development of the adrenergic system.