Jakab G, Szallasi A, Agoston D
Laboratory of Experimental Neuropathology, NINDS, NIH, Bethesda, MD 20892.
Brain Res Dev Brain Res. 1994 Jul 15;80(1-2):290-4. doi: 10.1016/0165-3806(94)90116-3.
Calcitonin gene-related peptide (CGRP) immunoreactivity was detected at day 2 in vitro (embryonic day 15) in developing mouse dorsal root ganglion (DRG) neurons in primary culture. During 2 weeks of culture the proportion of CGRP-immunoreactive (CGRP-IR) neurons remained around 65-70%, much higher than usually found in adult animals (45-50%). Treatment of cultures with the capsaicin analog resiniferatoxin (RTX; 0.3-30 nM) significantly augmented CGRP immunoreactivity per neuron at all ages investigated without increasing the number of CGRP-immunoreactive cells. The increased CGRP immunoreactivity was observed both in the axonal varicosities and in the perinuclear region of cell bodies. This RTX-induced increase in CGRP immunoreactivity was completely blocked by Ruthenium red (RR). Treatment with the non-esterified form of RTX (resiniferol 9, 13, 14 orthophenylacetate, ROPA) produced no increase. These results suggest that: (1) early expression of the CGRP phenotype is regulated in a cell-autonomous way in developing mouse DRG neurons in vitro; and (2) the RTX-induced increase in CGRP biosynthesis is most likely the result of activating the capsaicin/RTX receptor rather than directly activating the protein kinase C (PKC) pathway in vitro. The results may also reflect qualitative and quantitative differences in capsaicin/RTX sensitivity of sensory neurons between embryonal and adult ages.
在体外培养第2天（胚胎第15天），在原代培养的发育中小鼠背根神经节（DRG）神经元中检测到降钙素基因相关肽（CGRP）免疫反应性。在2周的培养期间，CGRP免疫反应性（CGRP-IR）神经元的比例保持在65%-70%左右，远高于成年动物中通常发现的比例（45%-50%）。用辣椒素类似物树脂毒素（RTX；0.3-30 nM）处理培养物，在所有研究的年龄段，每个神经元的CGRP免疫反应性均显著增强，而CGRP免疫反应性细胞的数量并未增加。在轴突曲张和细胞体的核周区域均观察到CGRP免疫反应性增加。这种RTX诱导的CGRP免疫反应性增加被钌红（RR）完全阻断。用RTX的非酯化形式（树脂醇9,13,14邻苯乙酸酯，ROPA）处理未产生增加。这些结果表明：（1）在体外培养的发育中小鼠DRG神经元中，CGRP表型的早期表达以细胞自主方式调节；（2）RTX诱导的CGRP生物合成增加很可能是激活辣椒素/RTX受体的结果，而不是在体外直接激活蛋白激酶C（PKC）途径。这些结果也可能反映了胚胎期和成年期感觉神经元对辣椒素/RTX敏感性的质和量的差异。
