Lundberg J M, Martling C R, Lundblad L
Department of Pharmacology, Karolinska Institute, Stockholm, Schweden.
Klin Wochenschr. 1988;66 Suppl 11:151-60.
Cigarette smoke-induced irritation of the nasal and tracheal mucosa induces both protective reflexes and vascular reactions (protein extravasation). The vapor phase of the smoke rather than the particulate phase containing nicotine seems to be mainly responsible for these reactions in the guinea pig and rat, and nicotine-free cigarettes also caused marked irritation. The vapor-phase components activate a specific type of sensory nerves, presumably belonging to the C-fibre group, which are sensitive to capsaicin. These nerves contain tachykinins and CGRP in their peripheral branches within the respiratory epithelium, around blood vessels, and in the bronchial smooth muscle layer. Tachykinins and CGRP are released from these sensory nerves upon acute chemical irritation by, for instance, capsaicin. Tachykinins are potent vasodilating agents and induce plasma-protein extravasation and bronchoconstriction, while CGRP mainly evokes vasodilatation. After pretreatment with high doses of capsaicin, tachykinins and CGRP are depleted from the sensory nerves which subsequently degenerate. The irritation in the nasal mucosa and the tracheal protein extravasation induced by cigarette smoke are absent in capsaicin-pretreated animals, while the mechanical sensitivity and efferent nerve function remain. Also the allergic reaction is reduced after capsaicin treatment, indicating that cigarette smoke and the mediators of the allergen response activate a common pathway.
香烟烟雾引起的鼻和气管黏膜刺激会引发保护性反射和血管反应（蛋白质外渗）。在豚鼠和大鼠中，烟雾的气相而非含尼古丁的颗粒相似乎是这些反应的主要原因，无尼古丁香烟也会引起明显的刺激。气相成分激活一种特定类型的感觉神经，大概属于C纤维组，它们对辣椒素敏感。这些神经在呼吸上皮内、血管周围和支气管平滑肌层的外周分支中含有速激肽和降钙素基因相关肽（CGRP）。速激肽和CGRP在受到如辣椒素等急性化学刺激时会从这些感觉神经中释放出来。速激肽是强效血管舒张剂，可诱导血浆蛋白外渗和支气管收缩，而CGRP主要引起血管舒张。用高剂量辣椒素预处理后，速激肽和CGRP会从感觉神经中耗尽，随后感觉神经会退化。在经辣椒素预处理的动物中，香烟烟雾引起的鼻黏膜刺激和气管蛋白外渗消失，而机械敏感性和传出神经功能仍保留。辣椒素治疗后过敏反应也会减轻，这表明香烟烟雾和过敏原反应的介质激活了一条共同途径。
