beta(3)-adrenoceptors control Cl- conductance in rabbit nasal epithelium

We have investigated the effects of beta (3)-adrenoceptor stimulation in vi vo on nasal epithelium. We have recorded the transepithelial potential diff erence in New Zealand white rabbit nostrils. Superfusion of the nasal epith elial surface with a Cl--free medium supplemented with amiloride, hyperpola rized the nasal potential difference. Isoprenaline produced a hyperpolariza tion of the nasal potential difference that was not prevented by nadolol, a potent beta (1)-/beta (2)-adrenoceptor antagonist, but was abolished by bu pranolol, a nonselective beta (1-3)-adrenoceptor antagonist. SR 58611 ((RS) -N-[(25)-7-ethoxycarbonylmethoxy- 1,2,3,4-teuahydronapht-2-yl-(2R)-2-(3-chl orophenyl)-2 hydroethanamine hydrochloride) and CGP 12177 (4-[3-t-butylamin o-3-hydroxypropoxy]benzimidazol-2-1), a preferential and a partial beta (3) -adrenoceptor agonists, respectively, also produced hyperpolarization of th e nasal potential difference. SR 59230 (3-(2-ethylphenoxy)-1-[(1S)1,2,3,4-t etrahydronaphth-1-ylaminol]-(2S)-2-propanol oxalate), a selective beta (3)- adrenoceptor antagonist, abolished the effects of CGP 12177. We conclude th at beta (3)-adrenoceptor stimulation resulted in modifications in the nasal potential difference. These findings strengthen the view that beta (3)-adr enoceptors are implicated in controlling water and salt transport in the no rmal respiratory epithelium. (C) 2001 Elsevier Science B.V. All rights rese rved.