title: Beta-adrenergic stimulation of ion transport in primary cultures of avian salt glands.
abstract: Adrenergic stimulation of transmural ion transport was identified and characterized in primary cultures of avian salt gland. Adrenergic activation was mediated by beta-receptors since stimulation of the short-circuit current (Isc) was blocked by propranolol but not phentolamine. The Isc's elicited by isoproterenol, epinephrine, and norepinephrine were dose dependent, with respective EC50 values of 1.5 X 10(-8) M, 5.0 X 10(-6) M, and 1.1 X 10(-5) M. The apparent Ki for propranolol inhibition after isoproterenol stimulation was 7.5 X 10(-10) M. 8-Br cyclic AMP (8-Br cAMP) and forskolin-elicited Isc's that were insensitive to propranolol, were potentiated by theophylline, and inhibited by furosemide or ouabain. Isoproterenol also induced an increase in ouabain-sensitive respiration in acutely dispersed cells from salt-stressed juvenile or unstressed adult animals, but not in fully salt-stressed adults. The data indicate that, in addition to the well-established cholinergic receptors, beta-adrenergic receptors can control ion transport in these glands. Furthermore, the results suggest for the first time that an intracellular effector pathway involving cAMP is present.
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001693:Biological Transport, Active; D002217:Carbachol / Q000494:pharmacology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D004372:Ducks; D004837:Epinephrine / Q000494:pharmacology; D005665:Furosemide / Q000494:pharmacology; D007477:Ions / Q000378:metabolism*; D007700:Kinetics; D010042:Ouabain / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012491:Salt Gland / Q000187:drug effects*
chemical_list: D000318:Adrenergic beta-Agonists; D007477:Ions; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; C016276:8-bromocyclic GMP; D010042:Ouabain; D001285:Atropine; D005665:Furosemide; D002217:Carbachol; D011433:Propranolol; D006152:Cyclic GMP; D004837:Epinephrine; D010646:Phentolamine