Simons C T, Kulchitsky V A, Sugimoto N, Homer L D, Székely M, Romanovsky A A
Thermoregulation Laboratory, Clinical Research and Technology, Legacy Holladay Park Medical Center, Portland, Oregon 97208, USA.
Am J Physiol. 1998 Jul;275(1):R63-8. doi: 10.1152/ajpregu.1998.275.1.R63.
Recent evidence has suggested a role of abdominal vagal afferents in the pathogenesis of the febrile response. The abdominal vagus consists of five main branches (viz., the anterior and posterior celiac branches, anterior and posterior gastric branches, and hepatic branch). The branch responsible for transducing a pyrogenic signal from the periphery to the brain has not as yet been identified. In the present study, we address this issue by testing the febrile responsiveness of male Wistar rats subjected to one of four selective vagotomies: celiac (CBV), gastric (GBV), hepatic (HBV), or sham (SV). In the case of CBV, GBV, and HBV, only the particular vagal branch(es) was cut; for SV, all branches were left intact. After the postsurgical recovery (26-29 days), the rats had a catheter implanted into the jugular vein. On days 29-32, their colonic temperature (Tc) responses to a low dose (1 microg/kg) of Escherichia coli lipopolysaccharide (LPS) were studied. Three days later, the animals were subjected to a 24-h food and water deprivation, and the effectiveness of the four vagotomies to induce gastric food retention, pancreatic hypertrophy, and impairment of the portorenal osmotic reflex was assessed by weighing the stomach and pancreas and measuring the specific gravity of bladder urine, respectively. Stomach mass, pancreas mass, and urine density successfully separated the four experimental groups into four distinct clusters, thus confirming that each type of vagotomy had a different effect on the indexes measured. The Tc responses of SV, CBV, and GBV rats to LPS did not differ and were characterized by a latency of approximately 40 min and a maximal rise of 0.7 +/- 0.1, 0.6 +/- 0.1, and 0.9 +/- 0.2 degrees C, respectively. The fever response of the HBV rats was different; practically no Tc rise occurred (0.1 +/- 0.2 degrees C). The HBV appeared to be the only selective abdominal vagotomy affecting the febrile responsiveness. We conclude, therefore, that the hepatic vagus plays an important role in the transduction of a pyrogenic signal from the periphery to the brain.
最近的证据表明，腹部迷走神经传入纤维在发热反应的发病机制中起作用。腹部迷走神经由五个主要分支组成（即腹腔前支和后支、胃前支和后支以及肝支）。负责将致热信号从外周传导至大脑的分支尚未确定。在本研究中，我们通过测试接受四种选择性迷走神经切断术之一的雄性Wistar大鼠的发热反应性来解决这个问题：腹腔迷走神经切断术（CBV）、胃迷走神经切断术（GBV）、肝迷走神经切断术（HBV）或假手术（SV）。在CBV、GBV和HBV的情况下，仅切断特定的迷走神经分支；对于SV，所有分支均保持完整。术后恢复（26 - 29天）后，将导管植入大鼠颈静脉。在第29 - 32天，研究它们对低剂量（1微克/千克）大肠杆菌脂多糖（LPS）的结肠温度（Tc）反应。三天后，使动物禁食禁水24小时，分别通过称量胃和胰腺的重量以及测量膀胱尿液的比重来评估四种迷走神经切断术诱导胃内食物潴留、胰腺肥大和肾门渗透反射受损的效果。胃质量、胰腺质量和尿液密度成功地将四个实验组分为四个不同的组群，从而证实每种类型的迷走神经切断术对所测量的指标有不同的影响。SV、CBV和GBV大鼠对LPS的Tc反应没有差异，其特征分别为潜伏期约40分钟，最大升高分别为0.7±0.1、0.6±0.1和0.9±0.2℃。HBV大鼠的发热反应不同；几乎没有Tc升高（0.1±0.2℃）。HBV似乎是唯一影响发热反应性的选择性腹部迷走神经切断术。因此，我们得出结论，肝迷走神经在将致热信号从外周传导至大脑中起重要作用。
