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CARDIOVASCULAR RESPONSIVENESS TO ARGININE VASOPRESSIN IN WATER‐LOADED AND SODIUM‐DEPLETED PREGNANT AND NON‐PREGNANT SHEEP
Author(s) -
Wintour E. Marelyn,
Coghlan John P.,
Congiu Mario,
Grim Clarence E.,
Laurence Brenda M.,
Meehan Peter J.,
McDougall John G.,
Scoggins Bruce A.
Publication year - 1987
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1987.tb00977.x
Subject(s) - vasopressin , bradycardia , medicine , endocrinology , heart rate , pregnancy , arginine , sodium , blood pressure , stroke volume , cardiac output , gestation , mean arterial pressure , chemistry , biology , amino acid , biochemistry , organic chemistry , genetics
SUMMARY 1. In conscious ewes pregnancy was associated with a significantly increased heart rate and cardiac output, while mean arterial pressure (MAP) and stroke volume were unchanged. 2. The present study examines the effect of arginine vasopressin (AVP) infused at 0.3, 1, 3.0, and 10 μg/h, into water‐loaded and sodium‐depleted ewes, either non‐pregnant or during the last third of gestation. 3. In the water‐loaded state, MAP rose significantly at the lowest rate of infusion in both pregnant and non‐pregnant ewes. Bradycardia occurred first at 0.3 μg/h in the pregnant ewes but not until 3.0 μg/h in the non‐pregnant animals. 4. In sodium deficiency there was no increase in MAP at any rate of infusion in either group. Bradycardia occurred in both groups at 1 μg/h. 5. This study shows that the pressor effects of AVP are unchanged by pregnancy. However, pregnant ewes are more sensitive to AVP‐induced bradycardia when the ewes are water‐loaded.