Norepinephrine content in guinea-pig nasal mucosa response to histamine and methacholine provocation

The effects of histamine and methacholine (cholinergic substance) on norepinephrine (NE) content in nasal mucosa of the guinea-pig has been investigated. Histamine application for seven consecutive days was found to reduce NE content on both sides of nasal mucosa with bilateral provocation and on the affected side with unilateral stimulation, whereas NE content increased on the unaffected side with unilateral application. Methacholine provocation enhanced NE content on both sides after the bilateral application to nasal mucosa and the affected side after the unilateral application, whereas there was no effect on the other side. Time course evaluation of NE content after unilateral histamine application demonstrated that NE content on the affected side was decreased 30 min after application, but was restored to a normal level by 120 min after application; there was no change on the other side. These results suggest that histamine promotes NE release in nasal mucosa although it possesses the inhibitory effect mediated by the parasympathetic nerve, suggesting that repeated histamine stimulation may deplete NE content and cause a functional disturbance of the sympathetic nerve predisposing patients to the non-specific nasal hypersensitivity observed in nasal allergy.