The effect of neuropeptide Y on mucociliary activity in the rabbit maxillary sinus

The effect of neuropeptide Y (NPY) on mucociliary activity in the rabbit maxillary sinus was investigated in vivo by injecting NPY at increasing dosages into the maxillary artery, response being recorded photoelectrically. At dosages of 0.1-5.0 micrograms/kg, NPY reduced mucociliary activity dose-dependently, the maximum decrease being 14.6 +/- 1.8%, at a dosage of 5.0 micrograms/kg. The NPY-induced reduction of the mucociliary activity manifested brief latency, the peak effect occurring within 3 min followed by a slow return to the baseline value 4-9 min after injection. The response of mucociliary activity to NPY remained unaffected by pretreatment with the alpha-adrenergic antagonists yohimbine (alpha 2) at 100.0 micrograms/kg and phentolamine (alpha 1 + alpha 2) at 0.2-1.0 mg/kg, indicating that the effect of NPY is not mediated via alpha-receptors. Pretreatment with the calcium antagonist nifedipine at 100.0 micrograms/kg inhibited the effect of NPY, suggesting that the NPY-induced decrease may be calcium dependent.