Hemorrhage decreases arterial pressure sooner in pregnant compared with nonpregnant dogs

Role of baroreflex

Virginia Brooks, L. C. Keil

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

This study was performed to test the hypothesis that smaller reflex increases in vasopressin, cortisol, adrenocorticotropic hormone (ACTH), and angiotensin II (ANG II) concentrations are produced by hemorrhage in pregnant compared with nonpregnant conscious dogs. Equivalent hemorrhages (1% of the initial blood volume per minute) produced larger decreases in arterial pressure [P <0.01; 107 ± 6 to 73 ± 10 mmHg (pregnant); 109 ± 6 to 90 ± 5 mmHg (nonpregnant)] but produced similar increases in plasma vasopressin concentration in the pregnant animals. As a result, the slope of the arterial pressure-to-vasopressin relationship was reduced (P <0.05). During pregnancy, smaller increases in plasma cortisol concentration and heart rate were also produced for a given decrease in arterial pressure, but the relationship between pressure and ACTH was not significantly affected. In contrast, higher levels of plasma renin activity and plasma ANG II concentration were achieved in the pregnant dogs. In general, the relationships between plasma hormone levels and either left or right atrial pressure were not significantly altered. These results indicate that reflex increases in heart rate, vasopressin, and cortisol concentration are attenuated in pregnant dogs and that this attenuation may contribute to the inability of pregnant animals to achieve normal cardiovascular homeostasis during hemorrhage.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume266
Issue number4 35-4
StatePublished - 1994

Fingerprint

Baroreflex
vasopressin
hemorrhage
Arterial Pressure
Vasopressins
Dogs
Hemorrhage
dogs
cortisol
Hydrocortisone
angiotensin II
corticotropin
reflexes
Angiotensin II
Adrenocorticotropic Hormone
Reflex
heart rate
Heart Rate
renin
Atrial Pressure

Keywords

  • adrenocorticotropic hormone
  • angiotensin II
  • blood pressure
  • cortisol
  • heart rate
  • renin
  • sympathetic nervous system

ASJC Scopus subject areas

  • Physiology
  • Agricultural and Biological Sciences(all)

Cite this

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abstract = "This study was performed to test the hypothesis that smaller reflex increases in vasopressin, cortisol, adrenocorticotropic hormone (ACTH), and angiotensin II (ANG II) concentrations are produced by hemorrhage in pregnant compared with nonpregnant conscious dogs. Equivalent hemorrhages (1{\%} of the initial blood volume per minute) produced larger decreases in arterial pressure [P <0.01; 107 ± 6 to 73 ± 10 mmHg (pregnant); 109 ± 6 to 90 ± 5 mmHg (nonpregnant)] but produced similar increases in plasma vasopressin concentration in the pregnant animals. As a result, the slope of the arterial pressure-to-vasopressin relationship was reduced (P <0.05). During pregnancy, smaller increases in plasma cortisol concentration and heart rate were also produced for a given decrease in arterial pressure, but the relationship between pressure and ACTH was not significantly affected. In contrast, higher levels of plasma renin activity and plasma ANG II concentration were achieved in the pregnant dogs. In general, the relationships between plasma hormone levels and either left or right atrial pressure were not significantly altered. These results indicate that reflex increases in heart rate, vasopressin, and cortisol concentration are attenuated in pregnant dogs and that this attenuation may contribute to the inability of pregnant animals to achieve normal cardiovascular homeostasis during hemorrhage.",
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