title: Atrial natriuretic peptide decreases contractility of cultured chick ventricular cells.
abstract: To determine whether atrial natriuretic peptide (ANP) has an inotropic effect, the contractility of spontaneously beating cultured chick embryo ventricular cells was studied in response to rat-ANP (1-23) superfused at concentrations ranging from 10(-10) M to 2.5 x 10(-7) M. r-ANP reversibly decreased contractility with a threshold concentration of 10(-8) M; at the highest concentration, r-ANP decreased contractility to a moderate extent (-30 +/- 4%) r-ANP increased dose-dependently intracellular cGMP levels. Stimulation of contractility with [Ca2+], the calcium-channel agonist BAY K 8644 or isoproterenol attenuated to various degrees the inhibitory effect of r-ANP. By contrast, the inhibitory effect of r-ANP on contractility was unchanged or even enhanced after stimulation of contractility by angiotensin II. There was no difference in r-ANP-induced increase in cGMP whether cells were pre-incubated with angiotensin II or not. These results indicate that r-ANP was able to decrease contractility of cultured cardiac myocytes and suggest a preferential antagonism of the inotropic effect of angiotensin II.
authors: INSERM U228, Paris, France.
authors: J F
authors: JF
authors: Vaxelaire
authors: S
authors: S
authors: Laurent
authors: P
authors: P
authors: Lacolley
authors: V
authors: V
authors: Briand
authors: H
authors: H
authors: Schmitt
authors: J B
authors: JB
authors: Michel
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D000242:Cyclic AMP / Q000032:analysis; D006152:Cyclic GMP / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects*; D006352:Heart Ventricles / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects*
chemical_list: D015220:Calcium Channels; D000804:Angiotensin II; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D006152:Cyclic GMP; D007545:Isoproterenol; D002118:Calcium