| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
AJP - Regulatory, Integrative and Comparative Physiology, Vol 266, Issue 1 215-R220, Copyright © 1994 by American Physiological Society
ARTICLES |
B. J. Koos, B. A. Mason and M. G. Ervin
Department of Obstetrics and Gynecology, Nicholas S. Assali Perinatal Research Laboratory, University of California at Los Angeles 90024.
The effects of adenosine on plasma arginine vasopressin (AVP) concentrations were determined in chronically catheterized fetal sheep (> 0.8 term). Infusion of adenosine [0.35 +/- 0.01 (SE) mg.min-1.kg-1] into the inferior vena cava of six fetuses caused a transient fall in arterial PO2 (by approximately 3 Torr), a slight reduction in arterial pH, and a 5- to 6-mmHg decrease in diastolic pressure without significantly affecting systolic or mean arterial values. A lower rate of infusion (0.19 +/- 0.01 mg.min-1 x kg-1) in five fetuses had virtually no effect on arterial blood gases, pH, or arterial pressures. Both the low- and high-dose adenosine infusions significantly increased fetal plasma AVP concentrations (1.7 +/- 0.2 to 25 +/- 7 pg/ml and 1.6 +/- 0.1 to 54 +/- 8 pg/ml, respectively). Intravenous infusion of papaverine lowered fetal diastolic and mean arterial pressures by approximately 8 mmHg but had no significant effect on plasma levels of AVP. During an hour of isocapnic hypoxia (arterial PO2 12-13 Torr), fetal plasma AVP levels increased from 1.7 +/- 0.2 to 40 +/- 6 pg/ml. Intra-arterial infusion of the adenosine receptor antagonist 8-(p-sulfophenyl)-theophylline significantly blunted the hypoxia-induced rise in plasma AVP concentrations to a maximum mean level of 11 +/- 6 pg/ml. These results indicate that 1) adenosine causes a dose-dependent increase in plasma AVP concentrations and 2) a hypoxia-induced rise in fetal adenosine levels triggers vasopressin release.
This article has been cited by other articles:
|
|
 |
|
  D. A. Giussani, D. S. Gardner, D. T. Cox, and A. J. W. Fletcher Purinergic contribution to circulatory, metabolic, and adrenergic responses to acute hypoxemia in fetal sheep Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2001; 280(3): R678 - R685. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. J. Koos and T. Maeda Adenosine A2A receptors mediate cardiovascular responses to hypoxia in fetal sheep Am J Physiol Heart Circ Physiol, January 1, 2001; 280(1): H83 - H89. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. E. Wood and H. Tong Central nervous system regulation of reflex responses to hypotension during fetal life Am J Physiol Regulatory Integrative Comp Physiol, December 1, 1999; 277(6): R1541 - R1552. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Braaksma, A. C. M. Dassel, and J. G. Aarnoudse Renal responses to prolonged (48 h) hypoxemia without acidemia in the late-gestation ovine fetus Am J Physiol Regulatory Integrative Comp Physiol, August 1, 1999; 277(2): R395 - R402. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Chau and B. J. Koos Metabolic and cardiorespiratory responses to hypoxia in fetal sheep: adenosine receptor blockade Am J Physiol Regulatory Integrative Comp Physiol, June 1, 1999; 276(6): R1805 - R1811. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. J. Koos, A. Chau, M. Matsuura, O. Punla, and L. Kruger Thalamic Locus Mediates Hypoxic Inhibition of Breathing in Fetal Sheep J Neurophysiol, May 1, 1998; 79(5): 2383 - 2393. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
