引用

总的来说，后梯形核(RTN)和相邻的C1神经元调节呼吸、循环和警觉状态，但以前控制这些神经元活动的方法缺乏足够的选择性，无法解析出它们的相对作用。我们假设RTN和C1神经元调节呼吸的不同方面(例如频率、振幅、主动呼气、叹息)，并在从睡眠中产生唤醒的能力上有所不同。我们在成年雄性和雌性Th- cre大鼠中使用光遗传学和病毒载体组合，以ChR2选择性转导RTN (Phox2b+/Nmb+)或C1神经元(Phox2b+/Th+)。RTN光刺激适度增加了唤醒的概率。RTN刺激显著增加呼吸频率和幅度;它还引发了强烈的主动呼气，但不是叹息。与这些反应一致的是，RTN支配整个桥髓呼吸网络，包括尾腹呼吸组(cVRG)的呼气前运动神经元，但RTN对调节觉醒的脑干区域(蓝斑，CGRP+臂旁神经元)的投射非常有限。C1神经元刺激产生了强烈的唤醒，与RTN刺激相比，呼吸频率和振幅增加相似，但引起了叹息和主动呼气缺席。与RTN不同的是，C1神经元支配蓝斑，CGRP+过程在臂旁复合体内，缺乏对cVRG的投射。总之，刺激C1或RTN可激活呼吸，但只有RTN神经元刺激产生主动呼气，这与它们作为中枢呼吸化学感受器的作用一致。 Conversely, C1 stimulation strongly stimulates ascending arousal systems and sighs, consistent with their postulated role in acute stress responses. SIGNIFICANCE STATEMENT: The C1 neurons and the retrotrapezoid nucleus (RTN) reside in the rostral ventrolateral medulla. Both regulate breathing and the cardiovascular system but in ways that are unclear because of technical limitations (anesthesia, non-selective neuronal actuators). Using optogenetics in unanesthetized rats, we found that selective stimulation of either RTN or C1 neurons activates breathing. However, only RTN triggers active expiration, presumably because RTN, unlike C1 has direct excitatory projections to abdominal premotor neurons. The arousal potential of the C1 neurons is far greater than that of the RTN, however, consistent with C1’s projections to brainstem wake-promoting structures. In short, C1 neurons orchestrate cardiorespiratory and arousal responses to somatic stresses whereas RTN selectively controls lung ventilation and arterial PCO2 stability.