Mechanism of action of extracellular calcium on isoprenaline‐evoked amylase secretion from isolated rat parotid glands.

Abstract

SUMMARY1. The effects of extracellular Ca2+ deprivation on amylase secretion, 45Ca efflux and cyclic adenosine 3',5'-monophosphate (cyclic AMP) metabolism were investigated in incubated parotid glands of young rats.2. Reducing the extracellular Ca2+ concentration from 2-5 x 10-3M to 10-6 M had no effect on amylase secretion but did increase the rate of 45Ca efflux from unstimulated glands.3. Isoprenaline (10-5M) increased amylase secretion and the rate of 45Ca efflux in media containing 2-5 x 10-3M-Ca2+, and also increased the parotid cyclic AMP content. 4. When glands were pre-incubated for either 10, 20, or 30 min in media containing

The effect of cyclosporine A and trifluoperazine on amylase secretion from rat parotid glands in vitro

“…In this study we show that CsA inhibits isoproterenol-stimulated amylase secretion from rat parotid glands in a dose-dependent manner (fig 1A and B). Since the isoproterenol-induced amylase release is mediated through cAMP and Ca2+dependent pathways (Argent and Arkle, 1985), it seems reasonable to assume that the concept that the observed effect of CsA on amylase secretion may be due to its interaction with the regulation of cAMP and/or CaZ+-dependent pathways.…”

“…One piece of parotid gland from each rat, with a total weight of about 100 mg, was cut into pieces and equilibrated, separately for each rat, in an organ bath containing 10 ml of KRT solution in the presence of atropine sulphate, 20 p M and phenoxybenzamine HCl, 10 pM (Argent and Arkle, 1985;Arkle et al, 1986) for 20 minutes at 37°C while shaking continuously at 90 cycle/ min. During the experiments, the KRT solution was oxygenated.…”

“…During the experiments, the KRT solution was oxygenated. The test drugs (CsA and/or TFP) were administered after the equilibration period and 10 pM IPR (Kanagasuntheram and Lim, 1981;Argent and Arkle, 1985) was added 80 minutes after incubation with the test drugs (Arkle er al, 1986). In the controls, equivolume amounts of the solvent (olive oil and water as vehicles of CsA and TFP, respectively) were administered.…”

Inhibitory effects of calmodulin antagonists on isoproterenol- and dibutyryl cyclic AMP-stimulated amylase release from rat parotid acinar cells.

“…Depletion of intracellular Ca2+ by incubation of rat parotid slices in media containing EGTA decreases the amylase release stimulated by (3-adrenergic agonists and cyclic AMP derivatives (1)(2)(3). These secretagogues increase the 45Ca efflux from rat parotid slices or dissociated acinar cells (2)(3)(4)(5).…”