The cholinergic receptor-regulation of K+ transport was studied in human submandibular glands. Acetylcholine stimulation 10 μmol/L results in an increase in membrane permeability (86Rb+ efflux) for, and a net efflux of, K+ ions from the glandular tissue. In the post-stimulus period, there is a net re-uptake of K+ ions into the tissue. Patch-clamp electrophysiological techniques were employed to demonstrate the presence of a large conductance K+ selective ion channel in the basolateral membranes of isolated human submandibular acinar cells. The patch-clamp results indicate that this voltage- and calcium-activated K+ channel operates to regulate the K+ permeability in both the resting and acetylcholine-stimulated acinar cells. We discuss the role of the K+ channel, K+ efflux, and K+ re-uptake in relation to stimulus-secretion coupling. © 1987, SAGE Publications. All rights reserved.