This study was performed to investigate the chemoreception of trigeminal afferents in the
nose. Single unit activity was recorded from the anterior ethmoidal nerve in the anesthetized
guinea pig breathing through a tracheostomy during nasal instillation of capsaicin (0.3 mM),
nicotine (6 mM) and ammonia (1.5 M) solutions or with distilled water. Out of 36 fibers
recorded, nineteen were stimulated by capsaicin, six by nicotine and seventeen by
ammonia. Among those of fibers, two were stimulated by both capsaicin and nicotine, six by …