Muscarinic acetylcholine receptors on human lymphocytes in patients with Menière's disease.

To investigate patients with Menière's disease and the association of cholinergic hyperreactivity, we performed muscarinic acetylcholine receptor assay using peripheral blood lymphocytes from patients with Menière's disease and non-dizzy, non-allergic control subjects. Cholinergic receptor maximal bindings (Bmax) and dissociation constants (Kd) were compared between the two groups, indicating the number and the affinities of the receptors, respectively. The receptor Bmax value in Meniére's patients during the remission state (108.6 +/- 51.2 fmol/l x 10(6) lymphocytes) was higher than that in normal controls (45.8 +/- 9.2 fmol/l x 10(6) lymphocytes) (p < 0.01). Furthermore, during an exacerbated state, Bmax was increased significantly (223.7 +/- 90.2 fmol/l x 10(6) lymphocytes) compared to the remission state (p < 0.01). In contrast, Kd values for the receptor did not differ between the two groups. These results suggest that patients with Menière's disease have cholinergic hyperreactivity, which may be further upregulated during a state of exacerbation due to an increase in the number of cholinergic receptors.