Background: Acoustic rhinometry is a noninvasive method that uses sound waves to measure dimensions of the nasal cavity.
Methods: In this study, nasal patency was measured by acoustic rhinometry in allergic Beagle dogs sensitized to ragweed allergen. Ragweed (0.03-0.3%) or vehicle were administered intranasally in isoflurane-anesthetized dogs.
Results: The instillation of ragweed caused a dose-related decrease in nasal cavity volume and minimal cross-sectional area (Amin) without adverse systemic effects. Nasal cavity volume and Amin decreased within 30 minutes after instillation of the highest ragweed dose by 35.1 +/- 6.0% and 66.4 +/- 13.8%, respectively, and persisted for at least 90 minutes. Oral administration of alpha-adrenergic agonist, d-pseudoephedrine (3 mg/kg), or histamine H1 antagonist chlorpheniramine (10 mg/ kg) blocked the ragweed-induced nasal congestion.
Conclusion: These results suggest that the canine model may be used to study upper-airway diseases such as allergic rhinitis and to evaluate the pharmacologic activity of nasal decongestants.