Electrophysiology of Salivary Acinar Cells: Microelectrode Studies

Abstract

In 1955 Lundberg, using conventional Ling-Gerard microelectrodes, first recorded the intracellular membrane potential from acinar cells in the cat mandibular gland in vivo. Either parasympathetic or sympathetic nerve stimulation caused membrane hyperpolarization, which he termed the “secretory potential”. From subsequent studies (Lundberg 1957a,b,c) on the cat sublingual gland, he postulated that the stimulus-evoked secretory potentials were due to activation of an inwardly directed active transport mechanism for Cl^-. Since subsequent microelectrode studies on stimulus-evoked potential responses in many salivary glands could not be explained by Lundberg’s proposition, however, it was postulated instead that the stimulus-evoked membrane response was due to activations of conductive pathways permeable to K⁺ and Na⁺ and of the electrogenic Na⁺ pump, located in the basolateral membrane (see Petersen 1980; Gallacher and Petersen 1983). Recently, Suzuki and Petersen (1985) suggested instead that the stimulus-evoked potential response might be due to activation of a K⁺-conductive pathway and the electrogenic Na⁺ pump in the basolateral membrane plus activation of a Cl^--conductive pathway in the luminal membrane (see also Petersen and Gallacher 1988). This model was derived from one first postulated for the rectal gland of the dogfish (Hannafin et al. 1983).