title: Roles of adrenoceptors in isolated canine parietal cells.
abstract: Functional roles of adrenoceptors in parietal cells were pharmacologically investigated using isolated canine parietal cells. In the crude membranes obtained from preparations highly purified in parietal cells (> 95% of purity), the specific binding of [3H]dihydroalprenolol (DHA) was observed with a Kd value of 2.9 nM and Bmax of 234 fmol/mg protein, while the specific binding of [3H]prazosin and [3H]rauwolscine were not attained. Propranolol concentration-dependently reduced the specific binding of [3H]dihydroalprenolol with a Ki value of 2.6 nM. Isoproterenol concentration-dependently stimulated [14C]aminopyrine accumulation in preparations enriched in parietal cells (about 70% purity) with the maximum at 10 nM. Isoproterenol increased the content of cyclic AMP in preparations enriched in parietal cells (70%) with the maximum at 100 nM. The isoproterenol-induced stimulatory effect of [14C]aminopyrine accumulation in preparations enriched in parietal cells (70%) was completely abolished by 1 microM propranolol but not by 1 microM phentolamine. In the presence of 1 microM propranolol, 100 microM noradrenaline did not affect carbachol- and histamine-induced [14C]aminopyrine accumulation in preparations enriched in parietal cells (70%). The present study suggests that stimulation of beta-adrenoceptors located on canine parietal cells evokes acid production in a cyclic-AMP-dependent manner. Furthermore, a possibility arises that canine parietal cells are not the site of action of alpha-adrenoceptors in mediating inhibition of gastric acid secretion.
authors.affiliation: Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor.
authors.forename: K
authors.initials: K
authors.lastname: Yokotani
authors.forename: J
authors.initials: J
authors.lastname: Park
authors.forename: J
authors.initials: J
authors.lastname: DelValle
authors.forename: T
authors.initials: T
authors.lastname: Yamada
mesh_terms: D000818:Animals; D000242:Cyclic AMP / Q000502:physiology; D004285:Dogs; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000502:physiology*; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000502:physiology*
chemical_list: D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011433:Propranolol; D000242:Cyclic AMP; D007545:Isoproterenol; D009638:Norepinephrine; D010646:Phentolamine