备注：When the expression level of 3-adrenoceptor was lowered, CFTR was not activated under base-line conditions but became sensitive to 3-adrenoceptor stimulation (isoproterenol plus nadolol, SR 58611, or CGP 12177). This later effect was not prevented by protein kinase A inhibitors. Our results provide molecular evidence that CFTR but not mutated F508-CFTR is regulated by 3-adrenoceptors expression through a protein kinase