| Abstrakt: |
The α-adrenergic stimulation by phenylephrine of lacrimal gland protein secretion was pharmacologically characterized. Acini, prepared from rat exorbital lacrimal glands, were incubated with agonists, antagonists or both for 0-20 min. Peroxidase secretion, an index of protein secretion, was measured spectrophotometrically. Peroxidase secretion was stimulated by the α1-adrenergic agonists phenylephrine, norepinephrine and methoxamine but not by the α2-adrenergic agonist clonidine. The non-selective α-adrenergic antagonist phentolamine completely inhibited phenylephrine-induced secretion. The selective α1-adrenergic alkylating agent phenoxybenzamine and the selective α1-adrenergic antagonist prazosin partially inhibited phenylephrine-induced secretion. The α2-adrenergic antagonist yohimbine, the β-adrenergic antagonist timolol, and the dopaminergic antagonist haloperidol also inhibited phenylephrine-induced secretion but were 100-fold less potent than prazosin. It is concluded that phenylephrine activates an α1-adrenergic pathway, but not an α2-adrenergic, β-adrenergic or dopaminergic pathway, to stimulate lacrimal gland protein secretion from acini. Copyright 1994, 1999 Academic Press |
