Esteban I, Levanti B, Garcia-Suarez O, Germanà G, Ciriaco E, Naves F J, Vega J A
Departamento de Morfologia y Biologia Celular, Facultad de Medicina, Universidad de Oviedo, Spain.
Anat Rec. 1998 Jul;251(3):360-70. doi: 10.1002/(SICI)1097-0185(199807)251:3<360::AID-AR12>3.0.CO;2-M.
Increasing evidence suggests that, in addition to peripheral sensory and sympathetic neurons, the enteric neurons are also under the control of neurotrophins. Recently, neurotrophin receptors have been detected in the developing and adult mammalian enteric nervous system (ENS). Nevertheless, it remains to be established whether neurotrophin receptors are expressed in all enteric neurons and/or in glial cells and whether expression is a common feature in the enteric nervous system of all mammals or if interspecific differences exist. Rabbit polyclonal antibodies against Trk proteins (regarded as essential constituents of the high-affinity signal-transducing neurotrophin receptors) and p75 protein (considered as a low-affinity pan-neurotrophin receptor) were used to investigate the cell localization of these proteins in the ENS of adult man, horse, cow, sheep, pig, rabbit, and rat. Moreover, the percentage of neurons displaying immunoreactivity (IR) for each neurotrophin receptor protein was determined. TrkA-like IR and TrkC-like IR were observed in a neuronal subpopulation in both the myenteric and submucous plexuses, from esophagus to rectum in humans, and in the jejunum-ileum of the other species. Many neurons, and apparently all glial cells, in the human and rat enteric nervous system also displayed p75 IR. TrkB-like IR was found restricted to the glial cells of all species studied, with the exception of humans, in whom IR was mainly in glial cells and a small percentage of enteric neurons (about 5%). These findings indicate that the ENS of adult mammals express neuronal TrkA and TrkC, glial TrkB, and neuronal-glial p75, this pattern of distribution being similar in all examined species. Thus, influence of specific neurotrophins on their cognate receptors may be considered in the physiology and/or pathology of the adult ENS.
越来越多的证据表明，除了外周感觉神经元和交感神经元外，肠神经元也受神经营养因子的控制。最近，在发育中和成年哺乳动物的肠神经系统（ENS）中检测到了神经营养因子受体。然而，神经营养因子受体是否在所有肠神经元和/或神经胶质细胞中表达，以及这种表达是否是所有哺乳动物肠神经系统的共同特征，或者是否存在种间差异，仍有待确定。针对Trk蛋白（被视为高亲和力信号转导神经营养因子受体的重要组成部分）和p75蛋白（被视为低亲和力泛神经营养因子受体）的兔多克隆抗体，用于研究这些蛋白在成年人类、马、牛、羊、猪、兔和大鼠的ENS中的细胞定位。此外，还确定了对每种神经营养因子受体蛋白显示免疫反应性（IR）的神经元百分比。在人类从食管到直肠的肌间神经丛和黏膜下神经丛的神经元亚群中，以及在其他物种的空肠-回肠中，观察到了TrkA样IR和TrkC样IR。在人类和大鼠的肠神经系统中，许多神经元以及显然所有的神经胶质细胞也显示出p75 IR。除人类外，在所有研究的物种中，TrkB样IR仅限于神经胶质细胞，在人类中，IR主要存在于神经胶质细胞和一小部分肠神经元（约5%）中。这些发现表明，成年哺乳动物的ENS表达神经元TrkA和TrkC、神经胶质细胞TrkB以及神经元-神经胶质细胞p75，这种分布模式在所有检查的物种中相似。因此，在成年ENS的生理学和/或病理学中，可以考虑特定神经营养因子对其同源受体的影响。
