Cadieux A, Springall D R, Mulderry P K, Rodrigo J, Ghatei M A, Terenghi G, Bloom S R, Polak J M
Neuroscience. 1986 Oct;19(2):605-27. doi: 10.1016/0306-4522(86)90285-x.
The occurrence and distribution of calcitonin gene-related peptide (CGRP) immunoreactivity in the rat respiratory tract were investigated by means of immunocytochemistry and radioimmunoassay using antibodies raised in rabbits to synthetic rat CGRP. Substantial amounts of CGRP immunoreactivity (range 5-37 pmol/g) were detected in all parts of the respiratory tract, the highest being in the stem bronchus. Gel filtration chromatography of extractable CGRP immunoreactivity revealed one single peak, eluting at the position of synthetic rat CGRP. CGRP immunoreactivity was localized both in mucosal endocrine cells and nerve fibres from the larynx down to the peripheral lung. CGRP-immunoreactive endocrine cells were found singly in trachea and stem bronchi and in groups in intrapulmonary airways. They appeared at a late stage of gestation (17 days), reached a maximum number near term and decreased after birth to maintain a population similar to that of the adult animals by postnatal day 21. Similarly, CGRP-immunoreactive nerve fibres were first identified by day 18 of the gestation period and reached the adult distribution by postnatal day 21. CGRP-immunoreactive nerve fibres were localized among smooth muscle, seromucous glands, beneath and within the epithelium of the airways and around blood vessels. CGRP was also found in sensory ganglia and in motor end plates of the larynx musculature. Neonatal pretreatment with capsaicin caused a marked reduction in CGRP immunoreactivity of nerve fibres in the respiratory tracts as well as a less marked decrease in the population of CGRP-containing endocrine cells of the lung. No change was seen in motor end plates immunostaining. Vagal ligation experiments revealed that CGRP-immunoreactive nerve fibres travelling in the vagus originate mainly from neurons located in the jugular ganglion. Infranodosal right vagal ligation induced a marked loss in CGRP-immunoreactive nerves of the trachea, and of the ipsilateral stem bronchus, but no changes were observed in peripheral lung. By contrast infranodosal left side vagal ligation caused a decrease in CGRP-immunoreactive nerves of the ipsilateral lung and bronchus without affecting the peptide content in the trachea. Left vagal ligation also induced a marked increase in both the intensity of staining and number of CGRP-immunoreactive endocrine cells in the lung. We conclude that CGRP immunoreactivity is localized in both nerve fibres and endocrine cells and is associated principally with the afferent (sensory) innervation of the respiratory tract.(ABSTRACT TRUNCATED AT 400 WORDS)
采用免疫细胞化学和放射免疫分析法，使用兔抗合成大鼠降钙素基因相关肽（CGRP）抗体，研究了大鼠呼吸道中CGRP免疫反应性的发生和分布情况。在呼吸道的所有部位均检测到大量的CGRP免疫反应性（范围为5 - 37 pmol/g），其中主支气管中的含量最高。对可提取的CGRP免疫反应性进行凝胶过滤层析，显示出一个单一峰，其洗脱位置与合成大鼠CGRP的位置相同。CGRP免疫反应性定位于从喉到外周肺的黏膜内分泌细胞和神经纤维中。CGRP免疫反应性内分泌细胞在气管和主支气管中单个出现，在肺内气道中则成群出现。它们在妊娠后期（17天）出现，在足月时数量达到最多，出生后减少，到出生后第21天维持与成年动物相似的数量。同样，CGRP免疫反应性神经纤维在妊娠期第18天首次被识别，到出生后第21天达到成年分布。CGRP免疫反应性神经纤维定位于平滑肌、浆液黏液腺之间、气道上皮之下和内部以及血管周围。在感觉神经节和喉肌的运动终板中也发现了CGRP。新生儿用辣椒素预处理导致呼吸道神经纤维中CGRP免疫反应性显著降低，肺部含CGRP内分泌细胞的数量也有较轻微的减少。运动终板免疫染色未见变化。迷走神经结扎实验表明，在迷走神经中走行的CGRP免疫反应性神经纤维主要起源于位于颈神经节的神经元。结下右侧迷走神经结扎导致气管和同侧主支气管中CGRP免疫反应性神经明显减少，但外周肺未见变化。相比之下，结下左侧迷走神经结扎导致同侧肺和支气管中CGRP免疫反应性神经减少，但不影响气管中的肽含量。左侧迷走神经结扎还导致肺中CGRP免疫反应性内分泌细胞的染色强度和数量显著增加。我们得出结论，CGRP免疫反应性定位于神经纤维和内分泌细胞中，主要与呼吸道的传入（感觉）神经支配相关。（摘要截短至400字）
