Saleh T M, Cechetto D F
Stroke and Aging, Robarts Research Institute, and Department of Physiology, University of Western Ontario, Canada.
J Comp Neurol. 1996 Mar 11;366(3):390-405. doi: 10.1002/(SICI)1096-9861(19960311)366:3<390::AID-CNE2>3.0.CO;2-#.
Previous studies in our laboratory have shown that the peptides, neurotensin (NT), cholecystokinin (CCK), substance P (SP), somatostatin (SOM), and calcitonin gene-related peptide (CGRP), have a role in modulating ascending visceral sensory information from the nucleus of the solitary tract to the thalamus via a mandatory synapse in the parabrachial nucleus (PB). In this investigation, we examined the changes in the levels of these peptides detected by immunohistochemistry in response to cervical vagal stimulation in the inactin-anesthetized male Wistar rat. Paired control and experimental animals were instrumented to monitor blood pressure and heart rate. The vagus nerve was stimulated for 0.5, 2, or 4 hours, after which time the animals were perfused and the brains processed immunohistochemically for the Fos protein and the peptides NT, CCK, SP, SOM, and CGRP. Vagal stimulation for 1 hour produced large numbers of Fos-positive cells in the external lateral (el), external medial (em), and central lateral (cl) subnuclei of the PB (N = 3). Vagal stimulation produced a reduction in the level of immunolabeling for NT, SOM, and CCK in the el and em subnuclei of the PB. This depletion was present at 0.5 hour and increased in magnitude with the length of vagal stimulation, reaching a maximum after 4 hours. In contrast, the immunolabeling for SP and CGRP increased after 0.5 hour, reaching a maximum after 2 hours of vagal stimulation in the el and em subnuclei of the PB. After 4 hours of vagal stimulation, the immunolabeling for SP and CGRP was depleted in the two PB subnuclei. Thus, the neuropeptides NT, CCK, SP, SOM, and CGRP, which modulate the visceral sensory information in the PB, are influenced somewhat differentially by the level of activity in the vagus nerve.
我们实验室之前的研究表明，神经降压素（NT）、胆囊收缩素（CCK）、P物质（SP）、生长抑素（SOM）和降钙素基因相关肽（CGRP）等肽类物质，通过臂旁核（PB）中的一个强制突触，在调节从孤束核到丘脑的内脏感觉信息上行过程中发挥作用。在本研究中，我们检测了在肌动蛋白麻醉的雄性Wistar大鼠中，通过免疫组织化学检测到的这些肽类物质水平在颈迷走神经刺激后的变化。将配对的对照动物和实验动物进行仪器安装，以监测血压和心率。迷走神经被刺激0.5、2或4小时，之后对动物进行灌注，并对大脑进行免疫组织化学处理，以检测Fos蛋白以及NT、CCK、SP、SOM和CGRP等肽类物质。迷走神经刺激1小时后，在PB的外侧（el）、内侧（em）和中央外侧（cl）亚核中产生了大量Fos阳性细胞（N = 3）。迷走神经刺激导致PB的el和em亚核中NT、SOM和CCK的免疫标记水平降低。这种减少在0.5小时时就已出现，并随着迷走神经刺激时间的延长而增加，在4小时后达到最大值。相比之下，SP和CGRP的免疫标记在0.5小时后增加，在迷走神经刺激2小时后，在PB的el和em亚核中达到最大值。迷走神经刺激4小时后，两个PB亚核中SP和CGRP的免疫标记减少。因此，在PB中调节内脏感觉信息的神经肽NT、CCK、SP、SOM和CGRP，受到迷走神经活动水平的影响存在一定差异。
