Bałkowiec A, Szulczyk P
Department of Physiology, I Faculty of Medicine, Warsaw Medical School, Poland.
Neuroscience. 1992;48(1):159-67. doi: 10.1016/0306-4522(92)90346-4.
The resting and reflex-evoked activities of single postganglionic sympathetic neurons with axons in the right thoracic vagus were tested in chloralose-anaesthetized cats. The properties of a majority of neurons were found to be similar. Cardiac- and inspiration-related rhythmicities were present in the resting activity of sympathetic neurons. Their resting activity was not affected by hyperventilation which abolished phrenic nerve discharges. Systemic hypoxia (2 min; 8% O2 in N2) increased the activity of the neurons more effectively in the deafferented state than when both sinus nerves remained intact. Injection of 0.1 ml 1 M sodium bicarbonate saturated with CO2, which activates peripheral chemoreceptors in the right or left carotid sinus, usually evoked a decrease in sympathetic activity in animals with both sinus nerves intact. We concluded that activation of peripheral chemoreceptors may inhibit the activity of the sympathetic neurons with axons in the right thoracic vagus. We suggest that the described sympathetic neurons may be a functionally homogeneous population which may innervate the conducting system of the heart. The close localization of sympathetic and parasympathetic axons in the vagus nerve may facilitate sympathetic-parasympathetic interaction at the level of their endings in the heart.
在水合氯醛麻醉的猫身上，测试了轴突位于右侧胸段迷走神经的单个节后交感神经元的静息活动和反射诱发活动。发现大多数神经元的特性相似。交感神经元的静息活动中存在与心脏和吸气相关的节律性。它们的静息活动不受过度通气的影响，过度通气会消除膈神经放电。全身性缺氧（2分钟；氮气中8%氧气）在去传入状态下比双侧窦神经完整时更有效地增加神经元的活动。注射0.1毫升饱和二氧化碳的1 M碳酸氢钠，可激活右侧或左侧颈动脉窦的外周化学感受器，在双侧窦神经完整的动物中通常会引起交感活动的降低。我们得出结论，外周化学感受器的激活可能会抑制轴突位于右侧胸段迷走神经的交感神经元的活动。我们认为，所描述的交感神经元可能是一个功能上同质的群体，可能支配心脏的传导系统。迷走神经中交感和副交感轴突的紧密定位可能有助于在心脏末梢水平上的交感 - 副交感相互作用。
