Franco-Cereceda A, Rydh M, Lou Y P, Dalsgaard C J, Lundberg J M
Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Regul Pept. 1991 Feb 26;32(3):253-65. doi: 10.1016/0167-0115(91)90019-d.
Both endothelin-(ET) and calcitonin gene-related peptide- (CGRP) like immunoreactivity (-LI) were present in a variety of organs and neuronal tissue of the guinea-pig as determined by radioimmunoassay (RIA). Neuronal tissues like dorsal root ganglia (DRG) contained by far the highest levels of both ET- (65 +/- 11 pmol/g) and CGRP-LI (34 +/- 5 pmol/g). The tissue levels of ET-LI remained unchanged after 6-hydroxydopamine and capsaicin-pretreatment, while CGRP-LI was markedly reduced after capsaicin. Chromatographic characterization revealed that the main portion of ET-LI in the DRG, right atrium and lung corresponded to synthetic ET-1. Immunohistochemical studies showed the presence of ET-LI in a few neurons of intact DRG and many neurons in DRG cell-cultures, partly co-existing with CGRP-LI. In the neuronal cells of DRG cultures the ratio between the ET- and CGRP-LI was 1:27 compared to 2:1 in intact DRG. 24 h after ligation of the sciatic or vagal nerves no accumulation of ET-LI was observed above the ligation, while CGRP-LI was increased 4-5-fold. Transection (10 days) of the sciatic nerve caused a 85-95% depletion of CGRP-LI in the distal skin, gastrocnemius muscle and trunk below the transection site, while in the proximal portion of the nerve CGRP-LI increased. No effects on ET-LI in these tissues were observed after sciatic nerve transfection. In release experiments on DRG cell cultures. Langendorff heart preparations or perfused guinea-pig lungs, potassium (60 mM), capsaicin or antidromic nerve stimulation evoked a clear-cut increase in the supernatant levels of CGRP-LI, suggesting release, while no effect on the ET-LI concentration was observed in the effluent. Furthermore, anoxia failed to influence the outflow of ET-LI from the heart and lung. It is concluded that ET-1-LI is present in high levels in spinal ganglia and ET-LI occurs in afferent cell-bodies, but in comparison with CGRP, ET shows remarkable inertness upon various experimental conditions including no evidence for axonal transport, loss after denervation or release. The neuronal ET-LI seems to increase under culture conditions, however. The possible function for the high content of ET-LI in the intact guinea-pig peripheral nervous system remains to be elucidated and may mainly be related to a non-neuronal pool considering the relatively low content of ET-LI compared to CGRP in cultured DRG cells.
通过放射免疫分析（RIA）测定发现，内皮素（ET）和降钙素基因相关肽（CGRP）样免疫反应性（-LI）存在于豚鼠的多种器官和神经组织中。背根神经节（DRG）等神经组织中ET-LI（65±11 pmol/g）和CGRP-LI（34±5 pmol/g）的含量最高。6-羟基多巴胺和辣椒素预处理后，ET-LI的组织水平保持不变，而辣椒素处理后CGRP-LI明显降低。色谱分析表明，DRG、右心房和肺中ET-LI的主要部分与合成的ET-1相对应。免疫组织化学研究显示，完整DRG的少数神经元和DRG细胞培养物中的许多神经元中存在ET-LI，部分与CGRP-LI共存。在DRG培养的神经元细胞中，ET-LI与CGRP-LI的比例为1:27，而在完整DRG中为2:1。坐骨神经或迷走神经结扎24小时后，结扎上方未观察到ET-LI的积累，而CGRP-LI增加了4-5倍。坐骨神经横断（10天）导致横断部位远端皮肤、腓肠肌和躯干中CGRP-LI减少85-95%，而神经近端的CGRP-LI增加。坐骨神经转染后，这些组织中的ET-LI未受影响。在DRG细胞培养物、Langendorff心脏标本或灌注的豚鼠肺的释放实验中，钾（60 mM）、辣椒素或逆向神经刺激可使CGRP-LI的上清液水平明显升高，表明有释放，而流出液中ET-LI浓度未受影响。此外，缺氧未能影响心脏和肺中ET-LI的流出。结论是，ET-1-LI在脊髓神经节中含量很高，ET-LI存在于传入细胞体中，但与CGRP相比，ET在各种实验条件下表现出明显的惰性，包括无轴突运输证据、去神经后丢失或释放。然而，在培养条件下，神经元ET-LI似乎会增加。完整豚鼠外周神经系统中ET-LI高含量的可能功能仍有待阐明，考虑到培养的DRG细胞中ET-LI与CGRP相比含量相对较低，其可能主要与非神经元池有关。
