Liberation of acetylcholine by ouabain in the cat submandibular gland

Summary

The ability of ouabain to initiate loss of potassium and salivary secretion from the perfused cat submandibular gland has been studied in the absence and presence of atropine. Ouabain (10⁻⁴ M) when given alone caused a net efflux of potassium amounting to 4.25 μEq×min⁻¹×g⁻¹ and induced salivary secretion. When ouabain was given together with atropine (7.2×10⁻⁵ M) the net efflux of potassium was 1.00 μEq×min⁻¹×g⁻¹ while no saliva was secreted.

In glands loaded with⁴²K the rate constant of the efflux of⁴²K was increased when the perfusion fluid contained ouabain. When atropine was given before and during administration of ouabain, there was no change in the rate constant.

The results indicate that ouabain causes a liberation of acetylcholine, which in turn increases the permeability of the glandular cells to potassium and elicits salivary secretion.