Pericardial pressure attenuates release of atriopeptin in volume-expanded dogs.
The role of the pericardium in the release of atriopeptin (AP) was examined, utilizing two separate protocols, in alpha-chloralose-anesthetized dogs. Protocol I consisted of an experimental group (9 dogs), in which the pericardium was incised to allow instrumentation and reapproximated, and a control group (6 dogs), in which the pericardium was left undisturbed. In the experimental group, mean right atrial pressure (Pra) was elevated from a control value of 1.8 +/- 0.9 mmHg (mean +/- SD) to 8.3 +/- 0.8 mmHg for 40 min by volume expansion with isoncotic, lactated Ringer solution. After this period of volume expansion, the pericardium was removed while holding Pra at 8 mmHg. During volume expansion, arterial blood samples for AP analysis were taken at 5, 10, 15, 20, 30, and 40 min, pre- and postpericardiectomy. A similar protocol was followed in the control group. At a Pra of 8 mmHg prepericardiectomy, the plasma AP concentration was 76 +/- 17 pM/l and 74 +/- 38 pM/l in the experimental and control groups, respectively. However, after pericardiectomy, AP levels increased significantly in both the experimental group (136 +/- 41 pM/l; P less than 0.001) and the control group (107 +/- 53 pM/l; P less than 0.025). In protocol II (6 dogs), the pericardium was removed before volume expansion, and Pra was elevated by 2- to 3-mmHg increments and maintained for periods of 13 min at each pressure. AP concentration did not increase until Pra reached 3-4 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)
Stone
J A
JA
Department of Medicine, University of Calgary, Faculty of Medicine, Alberta, Canada.
Wilkes
P R
PR
Keane
P M
PM
Smith
E R
ER
Tyberg
J V
JV
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood / Q000378:metabolism*; D001794:Blood Pressure; D001810:Blood Volume; D004285:Dogs; D006321:Heart / Q000502:physiology; D006339:Heart Rate; D007552:Isotonic Solutions; D010496:Pericardium / Q000502:physiology*; D010952:Plasma Substitutes; D012016:Reference Values; D000077325:Ringer's Lactate
D007552:Isotonic Solutions; D010952:Plasma Substitutes; D000077325:Ringer's Lactate; D009320:Atrial Natriuretic Factor