title: Bay K 8644, a voltage-sensitive calcium channel agonist, facilitates secretion of atrial natriuretic polypeptide from isolated perfused rat hearts.
abstract: Effects of Bay K 8644, a voltage-sensitive calcium channel agonist, on atrial natriuretic polypeptide (ANP) secretion from isolated rat hearts perfused with Krebs-Henseleit solution were investigated. After a ninety-min period for stabilization, coronary sinus effluents were collected every two min and ANP levels were measured by radioimmunoassay. The basal secretory rate of ANP was 1.65 +/- 0.15 ng/min (mean +/- standard error). Bay K 8644 stimulated ANP secretion dose-dependently. This stimulatory action was blocked by simultaneous administration of nifedipine, its competitive antagonist. Heart rate was also increased by Bay K 8644 administration. In the gel filtration study, the major secretory form of ANP corresponded to alpha-rat ANP, a 28-amino acid peptide. These results suggest that voltage-sensitive calcium channels are involved in two principal biological properties, contraction and ANP secretion, of atrial cardiocytes.
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D012636:Secretory Rate / Q000187:drug effects; D013997:Time Factors
chemical_list: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009320:Atrial Natriuretic Factor; D009543:Nifedipine