Calcium ion uptake induced by cholinergic and ?-adrenergic stimulation in isolated cells of rat salivary glands

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Abstract
Adrenaline (10−5 M) and carbamylcholine (10−4 M) stimulate45Ca2+ uptake into isolated cells of rat submandibular gland and parotid glands. In the presence of the α-adrenoreceptor blocking agent phentolamine, adrenaline stimulation of45Ca2+ uptake is abolished. The β-adrenergic stimulant isoproterenol has no effect on45Ca2+ uptake. Carbamylcholine induced45Ca2+ uptake is inhibited by atropine. The Ca2+ ionophore A23187 stimulates45Ca2+ uptake, whereas dibutyryl cyclic adenosine 3′,5′-monophosphate and dibutyryl cyclic guanosine 3′,5′-monophosphate have no effect on45Ca2+ uptake. A graphical analysis of the45Ca2+ uptake curves reveals at least two phases: a fast phase and a slow phase, both of which are stimulated by adrenaline and carbamylcholine. The45Ca-exchangeable pool size is increased by adrenaline and carbamylcholine in both the fast and the slow phases. These results suggest that α-adrenergic and cholinergic agonists act by increasing the rate of Ca2+ transfer into the cells of the parotid and submandibular salivary glands most probably through an increase of the cell membrane permeability for Ca2+.
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