Potassium release by α2-adrenergic receptor stimulation of rat parotid acinar cells

Abstract

alpha-Adrenergic stimulation elicited a rapid release of K+ from dispersed parotid acinar cells in the presence of external Ca2+. A recent classification of alpha-adrenergic receptors proposed that alpha 1 receptors facilitate Ca2+ entry while alpha 2 receptors interact with adenylate cyclase. We tested this proposal by studying the ability of selective alpha-adrenergic antagonists to prevent epinephrine-induced release of K+ from parotid cells. The alpha 1 agents, WB 4101 and prazosin, were less potent than the alpha 2 antagonist yohimbine. These data suggest that alpha 2-adrenergic receptors in the parotid might facilitate the entry of Ca2+.