Attenuation of allergen-evoked nasal responses by local pretreatment with exogenous neuropeptide Y in atopic patients.

BACKGROUND

Nasal obstruction and rhinorrhea present in allergic rhinitis are at least partly influenced by neuropeptides released from sensory, parasympathetic, and sympathetic nerves. Neuropeptide Y (NPY) is co-localized with norepinephrine in sympathetic perivascular nerves. NPY is released with norepinephrine on sympathetic nerve stimulation and produces long-lasting vasoconstriction of the nasal vascular bed. In addition to vasoconstriction, there is evidence to suggest that NPY modulates the release of transmitters originating from parasympathetic and sensory nerves by acting on prejunctional receptors. Putative therapeutic application of NPY in rhinitis has been recently suggested because intranasal administration of exogenous NPY in human beings reduces nasal airway resistance and vascular permeability without affecting submucosal gland secretion.

OBJECTIVE

The aim of this study was to determine whether intranasal pretreatment with exogenous NPY could influence the functional responses to subsequent allergen challenge.

METHODS

A randomized double-blind, three-way, crossover, placebo-controlled study was performed in 13 patients with allergic rhinitis. Pretreatments with NPY (20 nmol), oxymetazoline hydrochloride (20 nmol), or saline solution (NaCl 0.9%) were administered in one nostril 5 minutes before nasal challenge with grass pollen allergen (10,000 standardized quality units). The number of sneezes and the subjective evaluation of nasal itching obstruction, and rhinorrhea were recorded. Nasal airway resistance was measured by anterior rhinomanometry, and nasal secretions were weighed. Mean arterial pressure and heart rate were recorded by noninvasive methods.

RESULTS

The number of sneezes, nasal itching, and subjective rhinorrhea evoked by the allergen were similar after the three pretreatments. Subjective and objective increases in nasal airway resistance and mucus production induced by the allergen were significantly (p < 0.01) reduced after NPY pretreatment when compared with saline solution or oxymetazoline pretreatment. Mean arterial pressure and heart rate were not changed.

CONCLUSIONS

Local pretreatment with exogenous NPY reduces nasal obstruction and mucus secretion evoked by allergen challenge in allergic patients without modification of local itching and number of sneezes.