10924327 |
Mizuno Y, Ito Y, Aoyama M, Kume H, Nakayama S, Yamaki K: Imipramine inhibits Cl (-) secretion by desensitization of beta-adrenergic receptors in calu-3 human airway cells. Biochem Biophys Res Commun. 2000 Aug 11;274(3):620-5. Recent investigations have found that tetracyclic antidepressants like imipramine (IMP) have high-affinity sites not only in brain but also in mammalian lung. In the present study, we examined the effects of IMP on the Cl (-) secretion produced by isoproterenol (ISP), a beta-adrenergic receptor (beta-AR) agonist, in Calu-3 human airway cells. ISP applied in the basolateral solution generated a sustained short-circuit current that was abolished by diphenylamine-2-carboxylate, a Cl (-) channel blocker. IMP (0.01-1 mM) applied in the apical or basolateral solution for 30 min significantly inhibited the ISP-induced responses in a concentration-dependent manner, and the inhibitory effects of this drug were remarkable when applied from the apical rather than the basolateral side. ISP-induced responses were mimicked by forskolin- and 8-bromo-cyclic AMP-induced ones, but which were insensitive to IMP. These results indicate that IMP desensitizes the beta-AR on the basolateral membrane from the cytosolic side in Calu-3 cells. |
2(0,0,0,2) |