Abstract
The effects of two sympathomimetic drugs on mucociliary activity and mucosal blood flow in the rabbit maxillary sinus were investigated by using a photo-electric technique (mucociliary activity) and laser Doppler flowmetry (blood flow). The responses produced were compared with effects of ligation of the external carotid artery. The a1-agonist phenylpropanolamine (0.1-100 μg/kg) had no effect on the mucociliary activity, whereas the blood flow was reduced by 33.8±8.9% (mean ± SE) when the dose was 100 μg/kg. The a2-agonist xylometazoline (0.01-10.0 μg/kg) reduced mucociliary wave frequency by 21.6±4.6% (mean ± SE) (maximum) for the dose 10 μg/kg. The blood flow was reduced by xylometazoline in the interval 1.0 to 10.0 μg/kg, with a maximum decrease of 65.8±2.6% (mean ± SE) for the dose of 10 μg/kg. Ligature of the external carotid artery reduced blood flow by 76.0±4.6% (mean± SE), but did not significantly influence the mucociliary wave frequency. It is concluded that the decrease in mucociliary activity induced by a2-adrenoceptor agonists is not due to a reduced blood flow.