Department of Otolaryngology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
Am J Physiol Regul Integr Comp Physiol. 2012 Apr 15;302(8):R965-75. doi: 10.1152/ajpregu.00680.2011. Epub 2012 Jan 25.
The parabrachial and adjacent Kölliker-Fuse (PBN/KF) nuclei play a key role in relaying visceral afferent inputs to the hypothalamus and limbic system and are, thus, believed to participate in generating nausea and affective responses elicited by gastrointestinal (GI) signals. In addition, the PBN/KF region receives inputs from the vestibular system and likely mediates the malaise associated with motion sickness. However, previous studies have not considered whether GI and vestibular inputs converge on the same PBN/KF neurons, and if so, whether the GI signals alter the responses of the cells to body motion. The present study, conducted in decerebrate cats, tested the hypothesis that intragastric injection of copper sulfate, which elicits emesis by irritating the stomach lining, modifies the sensitivity of PBN/KF neurons to vertical plane rotations that activate vestibular receptors. Intragastric copper sulfate produced a 70% median change in the gain of responses to vertical plane rotations of PBN/KF units, whose firing rate was modified by the administration of the compound; the response gains for 16 units increased and those for 17 units decreased. The effects were often dramatic: out of 51 neurons tested, 13 responded to the rotations only after copper sulfate was injected, whereas 10 others responded only before drug delivery. These data show that a subset of PBN/KF neurons, whose activity is altered by a nauseogenic stimulus also respond to body motion and that irritation of the stomach lining can either cause an amplification or reduction in the sensitivity of the units to vestibular inputs. The findings imply that nausea and affective responses to vestibular stimuli may be modified by the presence of emetic signals from the GI system.
臂旁核和相邻的 Kölliker-Fuse（PBN/KF）核在将内脏传入输入中继到下丘脑和边缘系统方面发挥着关键作用，因此被认为参与了由胃肠道（GI）信号引起的恶心和情感反应的产生。此外，PBN/KF 区域接收来自前庭系统的输入，并可能介导与晕动病相关的不适。然而，以前的研究并未考虑 GI 和前庭输入是否会聚到相同的 PBN/KF 神经元，如果是这样，GI 信号是否会改变细胞对身体运动的反应。本研究在去大脑猫中进行，测试了这样一个假设，即向胃内注射硫酸铜会刺激胃壁，从而引发呕吐，这会改变 PBN/KF 神经元对激活前庭感受器的垂直平面旋转的敏感性。向胃内注射硫酸铜会使 PBN/KF 单位对垂直平面旋转的反应增益产生 70%的中位数变化，该化合物的给药会改变其放电率；16 个单位的反应增益增加，而 17 个单位的反应增益减少。这些影响通常是显著的：在测试的 51 个神经元中，有 13 个在注射硫酸铜后仅对旋转有反应，而另外 10 个在给药前仅对旋转有反应。这些数据表明，一组 PBN/KF 神经元的活动被致呕刺激改变，它们也对身体运动有反应，并且胃壁的刺激可以增加或减少单位对前庭输入的敏感性。这些发现意味着前庭刺激引起的恶心和情感反应可能会被来自 GI 系统的致呕信号所改变。
