Behavior of Cardiac Receptors with Nonmyelinated Vagal Afferents during Spontaneous Respiration in Cats
Behavior of Cardiac Receptors with Nonmyelinated Vagal Afferents during Spontaneous Respiration in Cats
复制标题
猫自主呼吸过程中非髓鞘迷走神经传入心脏受体的行为
DOI：
10.1161/01.res.41.5.694
复制
发表时间：
1977
影响因子：
20.1
通讯作者：
J. Shepherd
中科院分区：
文献类型：
--
作者：
M. Thames;J. Shepherd
在13只闭胸自发性呼吸猫，用三氯蔗糖麻醉，记录左房和左心室受体与非髓鞘迷走神经传入的活动(平均传导速度，1.2米/秒)。在实验结束时，通过探查开放的心脏来确定每个受体的解剖位置。在静息状态下，8个左房感受器中的3个和5个左心室感受器中的4个是静默的。显示自发活动的6个感受器在安静状态下的平均放电频率为1.0±0.15脉冲/秒。因此，具有迷走神经非髓鞘传入的心脏感受器在自发呼吸的猫中有较低的静息放电。在自主呼吸过程中，心房受体的放电频率和放电模式发生改变，而心室受体的放电频率和放电模式没有改变。当跨室壁压力最大时，心房感受器在吸气末期和早期呼气时有节律性放电，并在呼吸周期的其余时间保持沉默。当CO增加呼吸时，呼吸或血容量增加，放电速率与心房跨壁压成线性函数关系。在8只开胸猫和3只自主呼吸猫上，对11个无髓传入的脑室受体(平均传导速度为1.0m/s)进行分级扩容和苯肾上腺素注射。单纯提高左室舒张期末压可增加放电频率，随之而来的收缩压升高可导致放电的进一步增加。
SUMMARY Activity from left atrial and left ventricular receptors with nonmyelinated vagal afferents (mean conduction velocity, 1.2 m/sec) was recorded in 13 closed-chest spontaneously breathing cats anesthetized with achloralose. The anatomic position of each receptor was determined by probing the opened heart at the conclusion of the experiment. Three of eight left atrial receptors and four of five left ventricular receptors were silent under resting conditions. The mean discharge frequency under resting conditions for the six receptors displaying spontaneous activity was 1.0 ± 0.15 impulse/sec. Thus cardiac receptors with vagal nonmyelinated afferents have a low resting discharge in spontaneously breathing cats. The frequency and pattern of discharge of atrial but not of ventricular receptors was altered during spontaneous respiration. The atrial receptors discharged with cardiac rhythmicity during end inspiration and early expiration when transmural pressure was greatest and were silent for the remainder of the respiratory cycle. When respiration was augmented by CO, breathing or blood volume was increased, the rate of discharge was a linear function of atrial transmural pressure. Eleven ventricular receptors with nonmyelinated afferents (mean conduction velocity, 1.0 m/sec) were exposed to graded volume expansion and phenylephrine infusion in eight open-chest and three spontaneously breathing cats. Raising left ventricular enddiastolic pressure alone increased the frequency of discharge, and a concomitant increase in systolic pressure caused a further increase in firing.