Bradykinin Accelerates Mucociliary Activity in Rabbit Maxillary Sinus

Abstract

The in vivo effect of bradykinin on mucociliary (m.c.) activity in the rabbit maxillary sinus was investigated by administering the substance (0.01-10.0 μg/kg) via arteria maxillaris and recording the responses with a non-invasive photoelectric technique. Bradykinin accelerated the m.c. activity in a dose-dependent manner in the dose range 0.05-10.0 μg/kg. While the action of bradykinin was resistant to pretreatment with indomethacin 10.0 mg/kg, it was considerably weakened by the substance P antagonist [D-Pro²,D-Trp^7,9]SP 1 mg/kg. The initial effect of bradykinin was also suppressed by atropine, suggesting that bradykinin accelerates m.c. activity by a dual mechanism comprising both SP and acetylcholine. Bradykinin probably stimulates a reflex arc in the airways involving afferent SP neurons and efferent post-ganglionic parasympathetic neurons.

Key Words:

• mucociliary activity
• bradykinin
• substance P
• indomethacin
• atropine
• substance Plantagonists & inhibitors
• maxillary sinus