Secretory response of dispersed rat submandibular cells. I. Potassium release
Quissell, D.O.
American Journal of Physiology 238(3): C90-C98
1980
ISSN/ISBN: 0002-9513 PMID: 6102845 Document Number: 167089
The secretory response of dispersed rat submandibular cells as it relates to the net efflux of K+ following sympathomimetic and parasympathomimetic stimulation was evaluated. The cholinergic agonists acetylcholine and carbamylcholine had equal efficacy but dissimilar receptor affinity. Median effective concentrations (EC50's) were 1.7 .times. 10-7 M and 7.1 .times. 10-7 M, respectively. Pilocarpine was acting as a partial agonist and had an EC50 at 5.6 .times. 10-7 M. (-)-Norepinephrine and (-)-epinephrine had similar efficacy and potency with EC50's at 5.6 .times. 10-7 M and 3.8 .times. 10-7 M, respectively. (-)-Phenylphrine acts as a partial agonist with an EC50 at 3.8 .times. 10-6 M, whereas (-)-isoproterenol stimulation resulted in no net K+ efflux within the concentrations tested (10-8 M-10-3 M). Extracellular Ca2+, but not Mg2+, was required to elicit a net K efflux following either cholinergic or .alpha.-adrenergic stimulation.