title: Response of mouse proximal straight tubule and medullary thick ascending limb to beta-agonist.
abstract: Scatchard analysis of (3H)CGP-12177 and (125I)cyanopindolol (CYP) radioligand binding data revealed the presence of specific beta-adrenergic receptor-binding sites on microdissected mouse proximal straight and medullary thick ascending limb (mTAL) tubules. beta-Receptor (10(-6) M isoproterenol) stimulation of isolated perfused mTAL tubules produced a consistent hyperpolarization of the transepithelial potential that was blocked by propranolol (10(-6) M), a beta-receptor antagonist, and furosemide (10(-4) M), an inhibitor of the Na+/K+/2 Cl- triporter. In contrast, there was no electrogenic response to isoproterenol stimulation in isolated perfused proximal straight tubules. In summary, radioligand binding data show that both proximal straight and mTAL tubules possess beta-receptor-binding sites. Electrogenic transport in the mTAL can be modulated by beta-agonists, but there was no detectable electrogenic response to beta-receptor stimulation in proximal straight tubules.
authors.affiliation: Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: N S
authors.initials: NS
authors.lastname: Morgunov
authors.forename: Y D
authors.initials: YD
authors.lastname: You
authors.forename: D J
authors.initials: DJ
authors.lastname: Hirsch
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000378:metabolism; D000818:Animals; D004594:Electrophysiology; D005665:Furosemide / Q000494:pharmacology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology*; D007679:Kidney Medulla / Q000187:drug effects / Q000378:metabolism; D007684:Kidney Tubules / Q000187:drug effects* / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D010477:Perfusion; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism; D011412:Propanolamines / Q000378:metabolism; D011433:Propranolol / Q000494:pharmacology; D011869:Radioligand Assay; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism
chemical_list: D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C047975:cyanopindolol; D005665:Furosemide; D011433:Propranolol; D010869:Pindolol; D007545:Isoproterenol; C033394:CGP 12177