Al-Adrenoceptor-Mediated Secretion from the Anterior Nasal Glands of the Dog

The secretion of fluid from the anterior nasal glands in pentobarbital-anesthetized dogs was measured by absorption on filter papers that were weighed before and after insertion into the nose. The secretion was stimulated by the local effects of drugs present on the dried filter paper. Methacholine evoked a dose-related secretion that could be reduced by atropine. Phenylephrine caused a scanty but measurable secretion in a dose that is used in topical nasal decongestants. When this alpha-adrenoceptor-stimulating drug was tested in combination with different doses of methacholine, a large increase in secretion was obtained over that with methacholine used alone. The increased secretion evoked by the combination was abolished by the alpha-adrenoceptor blocking drug phentolamine.