Phillips Robert J, Baronowsky Elizabeth A, Powley Terry L
Purdue University, Department of Psychological Sciences, West Lafayette, Indiana 47907, USA.
J Comp Neurol. 2003 Jan 6;455(2):222-37. doi: 10.1002/cne.10470.
Vagal afferents regenerate, by 18 weeks after subdiaphragmatic transection, to reinnervate the gut and to differentiate into the two types of terminals normally found in the smooth muscle wall of the gastrointestinal (GI) tract (Phillips et al. [2000] J Comp Neurol. 421:325-346). Regeneration, however, is neither complete nor entirely accurate by 18 weeks. Moreover, the capacity of the vagal efferents to reinnervate the GI tract under comparable conditions has not been evaluated. Therefore, to determine whether a more extended postaxotomy survival interval would (1). result in more extensive reinnervation of smooth muscle, (2). facilitate correction of the inaccuracies of the regenerated axons and terminals, and (3). yield motor as well as sensory reinnervation of GI targets, Sprague-Dawley rats received either complete subdiaphragmatic vagotomies (n = 18) or sham surgeries (n = 12). Physiological endpoints that might normalize as vagal elements regenerated, including body weight, daily food intake, size of first daily meal, and metabolic efficiency, were monitored. At 45 weeks after the vagotomies, the animals were randomly assigned to afferent (wheat germ agglutinin-horseradish peroxidase) or efferent (cholera toxin subunit B-horseradish peroxidase) mapping conditions, and labeled axons and terminals in the stomach and first 8 cm of the small intestine were inventoried in whole-mounts. Afferent regeneration was more extensive at 45 weeks than previously observed at 18 weeks after surgery; however, the amount of GI innervation was still not comparable to the intact pattern of the sham rats. Furthermore, abnormal patterns of sensory organization occurred throughout the reinnervated field, with small bundles of axons forming complex tangles and some individual axons terminating in ectopic locations. The presence of growth cone profiles suggested that vagal reorganization was ongoing even 45 weeks after surgery. In contrast to this relatively extensive, albeit incomplete, sensory reinnervation of the gut, motor fibers had failed to reinnervate the GI tract. Thus, dramatic differences exist in the regenerative capacities of the sensory and motor arms of the vagus under the same surgical and maintenance conditions. Furthermore, the functional measures of disordered energy regulation did not normalize over the 45 weeks during which afferent but not efferent innervation was restored.
迷走神经传入纤维在膈下横断术后18周开始再生，重新支配肠道，并分化为胃肠道（GI）平滑肌壁中正常存在的两种终末类型（Phillips等人[2000]《比较神经学杂志》。421:325 - 346）。然而，到18周时，再生既不完全也不完全准确。此外，在类似条件下迷走神经传出纤维重新支配胃肠道的能力尚未得到评估。因此，为了确定更长的轴突切断术后存活时间是否会（1）。导致平滑肌的再支配更广泛，（2）。促进再生轴突和终末不准确之处的纠正，以及（3）。使胃肠道靶标的运动和感觉都得到再支配，将Sprague - Dawley大鼠分为完全膈下迷走神经切断术组（n = 18）或假手术组（n = 12）。监测了随着迷走神经成分再生可能恢复正常的生理终点，包括体重、每日食物摄入量、每日第一餐的量和代谢效率。在迷走神经切断术后45周，将动物随机分配到传入（小麦胚凝集素 - 辣根过氧化物酶）或传出（霍乱毒素亚基B - 辣根过氧化物酶）映射条件下，并对胃和小肠前8厘米中标记的轴突和终末进行整装片清点。45周时的传入神经再生比手术18周时先前观察到的更广泛；然而，胃肠道的神经支配量仍与假手术大鼠的完整模式不可比。此外，在整个再支配区域出现了感觉组织的异常模式，小束轴突形成复杂的缠结，一些单个轴突在异位位置终止。生长锥轮廓的存在表明即使在手术后45周迷走神经仍在重组。与这种相对广泛但不完全的肠道感觉再支配相反，运动纤维未能重新支配胃肠道。因此，在相同的手术和维持条件下，迷走神经的感觉和运动分支的再生能力存在显著差异。此外，在恢复传入但未恢复传出神经支配的45周期间，能量调节紊乱的功能指标并未恢复正常。
