Suppression of intercellular communication in acinar cells from rat submandibular gland by cholinergic and adrenergic agonists

The effects of cholinergic and adrenergic agonists on intercellular communication in isolated acini of rat submandibular gland were evaluated using dye-coupling. Cells injected with Lucifer Yellow CH showed diffusion of the dye to their coupled neighbors under the control condition. Addition of acetylcholine (ACh) and carbachol (CCh) at concentrations higher than 10(-6) M rapidly and reversibly suppressed the dye-coupling. This effect by 10(-4) M ACh or 10(-4) M CCh was blocked by the addition of 10(-6) M atropine. The suppressive effects of 10(-4) M adrenaline and 10(-4) M noradrenaline were weaker than those of 10(-4) M ACh. Treatment with 10(-4) M isoproterenol did not inhibit the dye-coupling and the suppressive effect by 10(-4) M adrenaline was blocked by the addition of 10(-5) M phenoxybenzamine. The inhibition of dye-coupling by ACh and adrenaline was blocked by the addition of 10(-5) M verapamil, 10(-4) M W-7 and 1.5 x 10(-5) M H-7, but not by 1.5 x 10(-5) M HA1004. These results suggest that the muscarinic action of cholinergic agonists and the alpha-action of adrenergic agonists might suppress the intercellular communication of the acinar cells in the rat submandibular gland, possibly through the increase of calcium influx and the activation of protein kinase C.