ABSTRACT
The pathophysiologic mechanism of nasal polyp remains poorly understood In the upper airway nitric oxide was found to be involved in function as diverse as regulation of smooth muscle tone, mediating inflammatory responses, mucosal defense mechanism, ciliary beat frequency, local homeostasis and mucus secretion as well as extracellular fluid transport. To show the difference in nitric oxide production in nasal polyp either bilateral ethmoidal or antrochoanal and allergic rhinitis and if it may have a rule in etiopathogenesis. The study was carried out on four groups, the control group [I]: 7 healthy subjects, group II: 12 patients with allergic rhinitis, group III: 10 patients with bilateral ethmoidal polypi and group VI: 8 cases of antrochoanal polyp. Histochemical search for inducible nitric oxide synthase enzyme [INOS] was don in the four groups. INOS was found to be double in allergic nasal mucosa and four times higher in ehmoidal polypi than control but in antrochoanal polyp it was very scanty or absent in many cases