title: Characterization of ANF receptors in cultured renal cortical vascular smooth muscle cells.
abstract: Because atrial natriuretic factor (ANF) has been demonstrated to decrease resistances in cortical renal vessels in vivo, we studied 125I-ANF binding and ANF-dependent guanosine 3',5'-cyclic monophosphate (cGMP) production in subcultured vascular smooth muscle cells (VSMC) prepared from the rabbit renal cortex. 125I-ANF specific binding at 4 degrees C represented 70% of total binding and reached a plateau at 30-60 min. Equilibrium saturation binding curves suggested one group of high-affinity receptor sites (KD = 78 +/- 16 pM, Bmax = 45 +/- 11 fmol/mg) but were compatible with several groups exhibiting close binding parameters. ANF, [Ala7,Ala23]ANF (a linear analogue), and C-ANF-(4-23) (a ligand of C receptors) inhibited 125I-ANF binding at 37 degrees C with nearly similar potencies. In contrast, at 4 degrees C, complete or nearly complete inhibition of binding was obtained with ANF and linear ANF, the latter exhibiting the weakest potency, whereas C-ANF-(4-23) displaced only 35% of the tracer. ANF markedly stimulated cGMP accumulation, with a threshold concentration of 10 pM and a stimulation of 115 times basal value at 0.1 microM. Linear ANF was also stimulatory with a much weaker potency. Around 25% of 125I-ANF bound to cell surface was internalized at 37 degrees C. Phenylarsine oxide partially inhibited internalization as well as the inhibitory potency of C-ANF-(4-23) on 125I-ANF binding. As shown by high-performance liquid chromatography extracellular 125I-ANF was rapidly degraded at 37 degrees C into its 125I-COOH-terminal tripeptide and 125I-Tyr.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institut National de la Santé et de la Recherche Médicale 64, Hôpital Tenon, Paris, France.
authors.forename: M L
authors.initials: ML
authors.lastname: Béa
authors.forename: J C
authors.initials: JC
authors.lastname: Dussaule
authors.forename: M
authors.initials: M
authors.lastname: Bens
authors.forename: R
authors.initials: R
authors.lastname: Ardaillou
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001667:Binding, Competitive; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D007457:Iodine Radioisotopes; D007672:Kidney Cortex / Q000098:blood supply*; D007700:Kinetics; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D011817:Rabbits; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D011956:Receptors, Cell Surface; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor; D006152:Cyclic GMP; D015056:1-Methyl-3-isobutylxanthine