Marino P L, Davies R O, Pack A I
Brain Res. 1981 Aug 31;219(2):289-305. doi: 10.1016/0006-8993(81)90292-4.
The activity of inspiratory cells in the region of the nucleus of the tractus solitarius (NTS) was recorded extracellularly in paralyzed, artificially ventilated cats either during chloralose-urethane anesthesia or following midcollicular decerebration. Twenty-three of the 68 inspiratory cells recorded in the region of the NTS were classified as I beta cells on the basis of their response to withholding lung inflation. The dynamic sensitivity of I beta cells was determined by studying their response to increases in the rate of lung inflation at constant peak volume. The I beta cells in this study showed 3 distinct patterns of response to increases in the rate of inflation. Five cells showed no change in firing pattern (fixed firing pattern). Ten cells showed an increase in the rate of rise of cell activity but no change in peak frequency (low dynamic sensitivity). Eight cells showed increases in both the rate of rise of cell activity and peak frequency (high dynamic sensitivity). It was concluded that I beta cells are not a functionally homogeneous population, at least in terms of their dynamic sensitivity. Cells showing fixed firing patterns have the characteristics of off-switch neurons. Cells with low levels of dynamic sensitivity may receive afferents from pulmonary stretch receptors. Cells showing a high degree of dynamic sensitivity may receive afferents from rapidly adapting receptors. The fact that I beta cells are not a functionally homogeneous population may explain the many divergent observations reported from studies of these cells.
在氯醛糖 - 乌拉坦麻醉期间或中脑水平去大脑后，对处于麻痹状态且人工通气的猫，在孤束核（NTS）区域的吸气细胞活动进行了细胞外记录。在NTS区域记录的68个吸气细胞中，有23个根据其对停止肺充气的反应被归类为Iβ细胞。通过研究Iβ细胞在恒定峰值容积下对肺充气速率增加的反应，确定了其动态敏感性。本研究中的Iβ细胞对充气速率增加表现出3种不同的反应模式。5个细胞的放电模式无变化（固定放电模式）。10个细胞的细胞活动上升速率增加，但峰值频率无变化（低动态敏感性）。8个细胞的细胞活动上升速率和峰值频率均增加（高动态敏感性）。得出的结论是，至少就其动态敏感性而言，Iβ细胞不是功能上均一的群体。表现出固定放电模式的细胞具有关断开关神经元的特征。动态敏感性低的细胞可能接受来自肺牵张感受器的传入神经。表现出高度动态敏感性的细胞可能接受来自快速适应感受器的传入神经。Iβ细胞不是功能上均一的群体这一事实，可能解释了对这些细胞研究报告中许多不同的观察结果。
