Effect of sinus denervation and vagotomy on c-fos expression in the nucleus tractus solitarius after exposure to CO2
Effect of sinus denervation and vagotomy on c-fos expression in the nucleus tractus solitarius after exposure to CO2
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DOI：
10.1007/bf02332172
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发表时间：
1996-04-01
影响因子：
4.5
通讯作者：
Chernick, V
中科院分区：
文献类型：
--
作者：
Jansen, AH;Nance, DM;Chernick, V
暴露于高碳酸血症和电刺激颈动脉窦神经（CSN）已被证明可诱导包括孤束核（NTS）在内的几个脑干区域的c-fos表达。为了测试标记的神经元是由高碳酸血症直接激活还是通过颈动脉体（窦神经）继发激活，成年大鼠暴露于空气或14-16%的二氧化碳中1小时。实验分为八组：(1)暴露于空气中，(2)暴露于CO？(3)慢性CSN去神经/CO2，(4)慢性单侧CSN去神经/CO2，(5)慢性假性CSN去神经/CO2，(6)麻醉/CO2，(7)麻醉和急性迷走神经切开术/CO2，(8)在暴露于CO2前20分钟预先注射吗啡，10 mg s.c。暴露于CO2或空气后，将大鼠麻醉，灌注4%多聚甲醛，用PAP（即过氧化物酶抗过氧化物酶）技术对脑进行c-fos蛋白免疫组织化学染色。利用显微镜和显像附片对NTS区域内每秒50 μ m的标记神经元进行计数，并绘制其位置。暴露于二氧化碳环境中的大鼠，其NTS中标记神经元的数量明显多于暴露于空气环境中的大鼠。其他干预措施，如CSN去神经、手术麻醉、迷走神经切开术或注射吗啡，对高糖血症暴露大鼠c-fos表达水平没有显著影响，表明中枢刺激而非继发性外周输入。这些反应神经元可能是广泛分布的中枢化学感受复合体的一部分。
Exposure to hypercapnia and electrical stimulation of the carotid sinus nerve (CSN) has been shown to induce c-fos expression in several brain stem regions including the nucleus tractus solitarius (NTS). To test whether the labeled neurons were activated directly by hypercapnia or secondarily via the carotid bodies (sinus nerve), adult rats were exposed to either air or 14-16% CO2 for 1 h. Experiments were done on eight groups: (1) exposure to air, (2) exposure to CO?, (3) chronic CSN denervation/CO2, (4) chronic unilateral CSN denervation/CO2, (5) chronic sham CSN denervation/CO2, (6) anesthetized/CO2, (7) anesthetized and acute vagotomy/CO2, and (8) premedicated with morphine, 10 mg s.c., 20 min before exposure to CO2. After exposure to CO2 or air the rats were anesthetized, perfused with 4% paraformaldehyde and the brains processed for immunohistochemical staining for c-fos protein using the PAP (i.e. peroxidase anti-peroxidase) technique. Labeled neurons in the area of the NTS in every second 50-mu m section were counted and their position plotted using a microscope and camera lucida attachment. Rats exposed to CO2 had a significantly greater number of labeled neurons in the NTS than those exposed to air. Other interventions, such as CSN denervation, surgery anesthesia, vagotomy or injection of morphine did not significantly affect the level of c-fos expression in rats exposed to hypercapnia, indicative of central stimulation rather than secondary peripheral input. These responsive neurons may be part of a widespread central chemoreceptive complex.