Nagai H, Tsuji F, Koda A
Department of Pharmacology, Gifu Pharmaceutical University, Japan.
J Pharmacobiodyn. 1990 Mar;13(3):195-9. doi: 10.1248/bpb1978.13.195.
The effect of substance P (SP) on the antigen-induced bronchoconstriction in vitro and in vivo was investigated in guinea pigs. SP caused the contraction of isolated non-sensitized guinea pig tracheal muscle at concentrations between 10(-9) to 10(-7) g/ml. The elimination of epithelium in the tracheal muscle produced a slight enhancement of SP response as compared to control. Antigen-induced contraction of isolated sensitized guinea pig tracheal muscle was slightly enhanced by the pretreatment with SP at a concentration of 10(-9) g/ml. The SP-induced enhancement of antigen-induced contraction was significantly augmented by the elimination of epithelium of sensitized tracheal muscle. Moreover, the clear bronchoconstriction was observed by the infusion of SP (1 micrograms/min) intravenously, but not by the infusion of SP at the rates between 0.1 and 0.01 micrograms/min. Antigen-induced asthmatic respiratory disorder was accelerated temporarily by the infusion of subthreshold SP (0.1 microgram/min). The reactivity of bronchial smooth muscle measured by repeated injection of acetylcholine was significantly potentiated by the infusion of subthreshold SP (0.1 microgram/min). These results suggest that SP has dual actions in the contractile response of guinea pig airway smooth muscle. One is the direct contractile activity, and the other one is enhancing activity of antigen- and acetylcholine-induced bronchoconstriction.
在豚鼠中研究了P物质（SP）对体外和体内抗原诱导的支气管收缩的影响。SP在10（-9）至10（-7）g/ml的浓度范围内可引起未致敏的豚鼠离体气管肌肉收缩。与对照组相比，气管肌肉上皮的去除使SP反应略有增强。用浓度为10（-9）g/ml的SP预处理可使致敏的豚鼠离体气管肌肉的抗原诱导收缩略有增强。去除致敏气管肌肉的上皮可显著增强SP诱导的抗原诱导收缩增强作用。此外，静脉注射SP（1微克/分钟）可观察到明显的支气管收缩，但以0.1至0.01微克/分钟的速率注射SP则未观察到。阈下剂量的SP（0.1微克/分钟）静脉输注可暂时加速抗原诱导的哮喘性呼吸紊乱。通过重复注射乙酰胆碱测量的支气管平滑肌反应性可被阈下剂量的SP（0.1微克/分钟）静脉输注显著增强。这些结果表明，SP在豚鼠气道平滑肌的收缩反应中具有双重作用。一种是直接收缩活性，另一种是增强抗原和乙酰胆碱诱导的支气管收缩活性。
