title: Responsiveness of the ANP providing system to volume load in conscious dogs.
abstract: We examined in detail changes in arterial plasma ANP concentration in response to volume load in conscious dogs. In a 5-min volume load experiment, 18 ml/kg of isosmotic and isooncotic 3% Dextran 40 in saline was infused over a period of 5 min. Mean left atrial pressure (MLAP) increased transiently by 7.6 +/- 0.9 mm Hg. Plasma ANP level (P-ANP) did not significantly increase. Assayed P-ANP levels were corrected for hemodilution. Corrected P-ANP (C-ANP) significantly increased from 206 +/- 17 to 348 +/- 34 pg/ml. However, the level of C-ANP did not reach a steady state. No significant linear correlation was found between increases in MLAP and normalized C-ANP. In a 45-min volume load experiment, the elevated level of MLAP caused by the 5-min volume load was maintained for 40 min by supplemental infusion. C-ANP significantly increased from 196 +/- 18 pg/ml to 435 +/- 73 ng/ml. The level of C-ANP reached a steady state. A close linear correlation was observed between increases in MLAP and normalized C-ANP. However, the peak time of C-ANP lagged 10 min behind MLAP. These results indicate that it takes 10 min for P-ANP to reach a steady state in fully responding to a volume load, and that the long-term volume load is a prerequisite to the response of the ANP providing system.
authors: Department of Physiology, Kagawa Medical School, Japan.
authors: Y
authors: Y
authors: Nishida
authors: A
authors: A
authors: Miyata
authors: H
authors: H
authors: Morita
authors: N
authors: N
authors: Uemura
authors: K
authors: K
authors: Kangawa
authors: H
authors: H
authors: Matsuo
authors: H
authors: H
authors: Hosomi
mesh_terms: D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood*; D001794:Blood Pressure; D001810:Blood Volume; D003911:Dextrans / Q000008:administration & dosage; D004285:Dogs; D006339:Heart Rate; D007262:Infusions, Intravenous; D013997:Time Factors
chemical_list: D003911:Dextrans; D009320:Atrial Natriuretic Factor