Cui Z H, Okazawa A, Skoogh B E, Lötvall J
Department of Clinical Pharmacology, Göteborg University, Gothenburg, Sweden.
Prostaglandins. 1997 Apr;53(4):263-77. doi: 10.1016/s0090-6980(97)89600-1.
Thromboxane A2 (TXA2) is a potent constrictor of both airway and vascular smooth muscle. In addition, plasma exudation is induced in the airways by a thromboxane mimetic (U-46619). Because plasma exudation is associated with a local vasodilatation and increased local blood flow, we hypothesized that the general vasoconstrictor effect of U-46619 would be weaker in the airways than in other vascular beds, perhaps resulting in increased local airway blood flow. We studied the effects of i.v. U-46619 on blood pressure, lung resistance as well as blood flow, plasma exudation in airways and leg skeletal muscle in guinea pigs. We found (1) i.v. U-46619 increases the systemic blood pressure, blood flow in tracheal mucosa but decreases blood flow in leg skeletal muscle; (2) i.v. U-46619 induces plasma exudation in the airways, but not in the leg skeletal muscle; (3) a positive relationship between blood pressure and tracheal blood flow as well as airway plasma exudation, a negative relationship between blood pressure and blood flow in leg skeletal muscle; (4) i.v. U-46619 significantly increases lung resistance. We conclude that i.v. U-46619 induces plasma exudation in airways but not in skeletal muscle, and that this plasma exudation is associated with the increased local blood flow, which in turn is caused by increased inflow pressure and redistribution of the total body blood flow to the airways.
血栓素A2（TXA2）是气道和血管平滑肌的强效收缩剂。此外，一种血栓素类似物（U - 46619）可诱导气道内血浆渗出。由于血浆渗出与局部血管舒张和局部血流增加有关，我们推测U - 46619的一般血管收缩作用在气道中比在其他血管床中更弱，这可能导致局部气道血流增加。我们研究了静脉注射U - 46619对豚鼠血压、肺阻力以及血流、气道和腿部骨骼肌血浆渗出的影响。我们发现：（1）静脉注射U - 46619可升高全身血压、增加气管黏膜血流，但减少腿部骨骼肌血流；（2）静脉注射U - 46619可诱导气道内血浆渗出，但不诱导腿部骨骼肌血浆渗出；（3）血压与气管血流以及气道血浆渗出呈正相关，血压与腿部骨骼肌血流呈负相关；（4）静脉注射U - 46619可显著增加肺阻力。我们得出结论，静脉注射U - 46619可诱导气道而非骨骼肌的血浆渗出，这种血浆渗出与局部血流增加有关，而局部血流增加又是由流入压力增加和全身血流重新分配至气道所致。
