Secretory response of dispersed rat submandibular cells. I. Potassium release.
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 were found to have equal efficacy but dissimilar receptor affinity. Median effective concentrations (EC50's) were 1.7 x 10(-7) M and 7.1 x 10(-7) M, respectively. Pilocarpine was found to be acting as a "partial" agonist and had an EC50 at 5.6 x 10(-7) M. (-)-Norepinephrine and (-)-epinephrine were found to have similar efficacy and potency with EC50's at 5.6 x 10(-7) M and 3.8 x 10(-7) M, respectively. (-)-Phenylephrine was found to act as a partial agonist with an EC50 at 3.8 x 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 shown to be required to elicit a net K efflux following either cholinergic or alpha-adrenergic stimulation.
D000109:Acetylcholine / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010276:Parasympatholytics / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology; D010862:Pilocarpine / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D013363:Submandibular Gland / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D010276:Parasympatholytics; D010862:Pilocarpine; D010656:Phenylephrine; D002217:Carbachol; D008274:Magnesium; D007545:Isoproterenol; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine; D004837:Epinephrine