Effects of carbachol on extracellular Na-dependent AIB uptake in rat parotid gland

• Published in: The American journal of physiology Vol. 239; no. 3; p. G183
• Main Authors: Keryer, G, Rossignol, B
• Format: Journal Article
• Language: English
• Published: United States 01.09.1980
• Subjects: Absorption; Aminoisobutyric Acids - metabolism; Animals; Biological Transport, Active - drug effects; Calcium - metabolism; Calcium - pharmacology; Carbachol - pharmacology; Depression, Chemical; In Vitro Techniques; Male; Parotid Gland - metabolism; Rats; Sodium - metabolism
• DOI: 10.1152/ajpgi.1980.239.3.g183
• ISSN: 0002-9513

In rat parotid glands the uptake of 2-[1-14C]aminoisobutyric acid (AIB), in vitro, depends on a Na concentration gradient between the intra- and extracellular medium. Ouabain (1 mM) which inhibits the Na+-K+-ATPase and a Na+ ionophore, monensin (which dissipates the Na+ gradient), both suppress this amino acid uptake. Carbachol (5 microM) (through muscarinic receptors) evokes a decrease in AIB uptake, and in the presence of 0.1 mM ouabain the cholinergic effect is enhanced. Ouabain alone (0.1 mM) very slightly depresses the [14C]AIB uptake. Neither 1 microM isoproterenol, nor 1 microM Ca2+ ionophore A23187, which affect the membrane potential in rat parotid acinar cells, modifies the AIB uptake. When the Ca is removed from the incubation medium, carbachol still evokes a small decreasing effect on AIB uptake. From these data we can suggest that the reduced AIB uptake (induced by the cholinergic agonist) appears to be related to a process dependent on variation of intracellular Na concentration that may be triggered by the cholinergic agonist.