NASAL CHOLINERGIC HYPERRESPONSIVENESS IN ATOPIC SUBJECTS STUDIED OUT-OF-SEASON

Background: Atopic individuals have previously been shown to have an a utonomic imbalance consisting of heightened cholinergic responsiveness in the lung, skin, and eyes, and beta-adrenergic hyporesponsiveness i n the lungs, eyes, and vasculature. This array of abnormalities is oft en accompanied by nonspecific bronchial hyperresponsiveness, as well a s alpha-adrenergic hyperresponsiveness in individuals with asthma. Met hods: To determine whether atopic individuals have intrinsic nasal air way hyperresponsiveness to methacholine, 21 nonatopic subjects and 37 subjects with allergic rhinitis were studied. All subjects were studie d out of their allergy seasons, and all allergy-related medications we re discontinued before the study began. Subjects underwent nasal chall enge with methacholine (1 to 25 mg), and lavaged nasal secretions were analyzed for total protein, the plasma marker albumin, and the glandu lar marker lactoferrin. Results: Atopic subjects demonstrated increase d glandular responsiveness to methacholine as evidenced by an increase in the secretion of lactoferrin in response to individual doses of me thacholine. Although the maximal lactoferrin secretion did not increas e, glandular sensitivity to methacholine was heightened because the do se of methacholine required to induce lactoferrin secretion achievable by 60% of the study population was significantly lower in the atopic group. The volume of lavaged secretions recovered and congestion score s were also higher in the atopic group as compared with the normal con trol group. Conclusions: These data strongly suggest that atopic indiv iduals have intrinsic nasal glandular hyperresponsiveness to cholinerg ic stimulation.