Tissue kallikrein stimulates mucociliary activity in the rabbit maxillary sinus

The in vivo effect of tissue kallikrein on the mucociliary activity in the rabbit maxillary sinus was investigated administering the substance (0.1-5 mU/kg) via a. maxillaris and recording the response with a non-invasive photoelectric technique. Tissue kallikrein accelerated mucociliary activity, with a maximum response for the dose 5 mU/kg (33.7 +/- 13.4% from basal levels, n = 5). The effect had a latency of abut 1 min, with a peak within 2-3 min after the beginning of the administration. The response to tissue kallikrein displayed tachyphylaxis with a second dose producing a weaker response. Pretreatment with the protease inhibitor aprotinin (10,000 KIU bolus/kg) inhibited the action of tissue kallikrein. Tissue kallikrein probably stimulates mucociliary activity by producing lysylbradykinin from kininogen. Bradykinin has in an earlier study been shown to stimulate mucociliary activity.