Tschirhart E, Bertrand C, Theodorsson E, Landry Y
Laboratoire de Neuroimmunopharmacologie, Université Louis Pasteur-Strasbourg I, Illkirch, France.
Naunyn Schmiedebergs Arch Pharmacol. 1990 Aug;342(2):177-81. doi: 10.1007/BF00166961.
Capsaicin (10(-9) to 10(-5) M) contracted guinea-pig tracheal strips. Epithelium-containing tracheal strips developed a maximum active tension which was significantly higher than that observed in epithelium-free strips. Anti-CGRP (calcitonin gene-related peptide) serum blocked the epithelium-dependent potentiation of the capsaicin-induced contraction in the intact tracheal strips, without affecting the response of the epithelium-free strips. This result suggests the occurrence of an epithelium-dependent release of CGRP. This same serum markedly reduced the contraction induced by exogenous rat CGRP in both intact and epithelium-free tracheal strips. In epithelium-free tracheal strips, capsaicin-induced contraction was abolished by spantide (10(-6) and 10(-5) M), a substance P antagonist, but, in intact tracheal strips, spantide did not abolish the capsaicin-induced contraction, showing that both CGRP and substance P release are directly induced by capsaicin. Moreover, the contractile responses to rat CGRP of intact tracheal strips from guinea pig suggest that CGRP itself might be able to release a contracting factor from the airway epithelium. Therefore, CGRP originating from the airway epithelium may play a major role in the control of airway smooth muscle tone.
辣椒素（10⁻⁹至10⁻⁵M）可使豚鼠气管条收缩。含有上皮的气管条产生的最大主动张力显著高于无上皮气管条。抗降钙素基因相关肽（CGRP）血清可阻断完整气管条中辣椒素诱导收缩的上皮依赖性增强，而不影响无上皮气管条的反应。这一结果提示存在上皮依赖性CGRP释放。同一种血清在完整和无上皮气管条中均显著降低了外源性大鼠CGRP诱导的收缩。在无上皮气管条中，辣椒素诱导的收缩可被P物质拮抗剂spantide（10⁻⁶和10⁻⁵M）消除，但在完整气管条中，spantide并未消除辣椒素诱导的收缩，表明CGRP和P物质的释放均由辣椒素直接诱导。此外，豚鼠完整气管条对大鼠CGRP的收缩反应提示CGRP本身可能能够从气道上皮释放一种收缩因子。因此，源自气道上皮的CGRP可能在气道平滑肌张力的控制中起主要作用。
