title: Effects of hypercalcemia and ouabain on plasma atrial natriuretic polypeptide in anesthetized dogs.
abstract: For the purpose of examining the role of calcium ion in the secretory process of atrial natriuretic polypeptide (ANP), we studied the effects of hypercalcemia and ouabain on plasma concentration of immunoreactive ANP (irANP). Pentobarbital sodium-anesthetized dogs were treated with calcium chloride infusion (0.136 mmol.kg-1.min-1, 10 min) or ouabain injection (30 micrograms/kg), and plasma irANP concentration, right atrial pressure, mean arterial pressure, heart rate, and serum calcium concentration were measured. To evaluate the effect of rising arterial pressure, plasma irANP concentration was also measured in dogs treated with phenylephrine hydrochloride (10 micrograms/kg). With calcium chloride infusion, serum calcium concentration and plasma irANP concentration, respectively, increased to about three times and about four times their basal levels. This increase of plasma irANP concentration was not attenuated by pretreatment with adrenoceptor blockers. Ouabain increased plasma irANP concentration to approximately 2.5 times the initial level. Neither calcium chloride nor ouabain produced any effect on right atrial pressure and heart rate, but both significantly increased mean atrial pressure. Phenylephrine caused a greater increase in mean arterial pressure than both calcium chloride and ouabain. However, there was no significant increase in plasma irANP concentration. These results suggest that the calcium ion may play a key role in the secretory process of ANP.
authors.affiliation: Department of Pharmacology, Kagawa Medical School, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Shouji
authors.forename: S
authors.initials: S
authors.lastname: Kimura
authors.forename: Y
authors.initials: Y
authors.lastname: Aki
authors.forename: A
authors.initials: A
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Fukui
authors.forename: H
authors.initials: H
authors.lastname: Iwao
authors.forename: Y
authors.initials: Y
authors.lastname: Abe
mesh_terms: D000768:Anesthesia, General; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood* / Q000378:metabolism; D002122:Calcium Chloride / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D006934:Hypercalcemia / Q000097:blood*; D007700:Kinetics; D008297:Male; D010042:Ouabain / Q000494:pharmacology*; D011863:Radioimmunoassay; D012016:Reference Values
chemical_list: D010042:Ouabain; D009320:Atrial Natriuretic Factor; D002122:Calcium Chloride