Pregnancy enhances the pressor response to thromboxane analogues in rabbits

G. Losonczy, J. P. Singh, M. Schoenl, I. Muchá, R. C. Venuto

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

In this study, we first tested the hypothesis that the previously demonstrated circulatory failure and thrombocytopenia induced by intracaval administration of thromboxane A2 (TxA2) analogues in nonpregnant (NP) rabbits [G. Losonczy, I. Mucha, J. DiPirro, J. Sweeney, G. Brown, J. Brentjens, and R. Venuto. Am. J. Physiol. 265 (Regulatory Integrative Comp. Physiol. 34): R772-R780, 1993] could be avoided if the compounds were given instead into the aortic arch. Conscious New Zealand White rabbits received bolus injections of U-46619 (5-20 μg) through a previously implanted catheter threaded into the aortic arch. Indeed, mean arterial pressure (MAP) rose modestly, and thrombocytopenia did not develop. Next, we compared the blood pressure responses of pregnant (P) rabbits with those of NP rabbits to intra-aortic U-46619 and I-BOP, because they had been found to be resistant to both the hypotensive and platelet aggregatory effects of intracaval U- 46619. Resting blood pressure was lower in P than in NP rabbits (74 ± 3 vs. 95 ± 2 mmHg), but showed a greater increase in response to U-46619. For example, following a 20-μg dose blood pressure rose 20 ± 0.3 mmHg in P vs. 12 ± 2.1 mmHg in NP rabbits (P <0.02). Similar results were obtained with the second TxA2 analogue I-BOP. Pregnancy-induced enhancement of blood pressure elevation may be the consequence of peripheral vasoconstriction, which was not seen in NP rabbits. Thus the actions of TxA2 analogues U- 46619 and I-BOP are markedly influenced by the route of administration. Furthermore, these compounds appear to be the only known vasoconstrictors whose prohypertensive effects are enhanced by normal pregnancy.

Original languageEnglish
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume269
Issue number3 38-3
Publication statusPublished - 1995

Fingerprint

Thromboxanes
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
Rabbits
Pregnancy
Thromboxane A2
Blood Pressure
Thoracic Aorta
Thrombocytopenia
Vasoconstrictor Agents
Vasoconstriction
Shock
Arterial Pressure
Blood Platelets
Catheters
Injections
7-(3-(3-hydroxy-4-(4'-iodophenoxy)-1-butenyl)-7-oxabicyclo(2.2.1)heptan-2-yl)-5-heptenoic acid

Keywords

  • eicosanoids
  • gestation
  • systemic hemodynamics

ASJC Scopus subject areas

  • Physiology

Cite this

Pregnancy enhances the pressor response to thromboxane analogues in rabbits. / Losonczy, G.; Singh, J. P.; Schoenl, M.; Muchá, I.; Venuto, R. C.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 269, No. 3 38-3, 1995.

Research output: Contribution to journalArticle

@article{c303a25645b8404ea3bed7cbc42ed12b,
title = "Pregnancy enhances the pressor response to thromboxane analogues in rabbits",
abstract = "In this study, we first tested the hypothesis that the previously demonstrated circulatory failure and thrombocytopenia induced by intracaval administration of thromboxane A2 (TxA2) analogues in nonpregnant (NP) rabbits [G. Losonczy, I. Mucha, J. DiPirro, J. Sweeney, G. Brown, J. Brentjens, and R. Venuto. Am. J. Physiol. 265 (Regulatory Integrative Comp. Physiol. 34): R772-R780, 1993] could be avoided if the compounds were given instead into the aortic arch. Conscious New Zealand White rabbits received bolus injections of U-46619 (5-20 μg) through a previously implanted catheter threaded into the aortic arch. Indeed, mean arterial pressure (MAP) rose modestly, and thrombocytopenia did not develop. Next, we compared the blood pressure responses of pregnant (P) rabbits with those of NP rabbits to intra-aortic U-46619 and I-BOP, because they had been found to be resistant to both the hypotensive and platelet aggregatory effects of intracaval U- 46619. Resting blood pressure was lower in P than in NP rabbits (74 ± 3 vs. 95 ± 2 mmHg), but showed a greater increase in response to U-46619. For example, following a 20-μg dose blood pressure rose 20 ± 0.3 mmHg in P vs. 12 ± 2.1 mmHg in NP rabbits (P <0.02). Similar results were obtained with the second TxA2 analogue I-BOP. Pregnancy-induced enhancement of blood pressure elevation may be the consequence of peripheral vasoconstriction, which was not seen in NP rabbits. Thus the actions of TxA2 analogues U- 46619 and I-BOP are markedly influenced by the route of administration. Furthermore, these compounds appear to be the only known vasoconstrictors whose prohypertensive effects are enhanced by normal pregnancy.",
keywords = "eicosanoids, gestation, systemic hemodynamics",
author = "G. Losonczy and Singh, {J. P.} and M. Schoenl and I. Much{\'a} and Venuto, {R. C.}",
year = "1995",
language = "English",
volume = "269",
journal = "American Journal of Physiology",
issn = "0363-6119",
publisher = "American Physiological Society",
number = "3 38-3",

}

TY - JOUR

T1 - Pregnancy enhances the pressor response to thromboxane analogues in rabbits

AU - Losonczy, G.

AU - Singh, J. P.

AU - Schoenl, M.

AU - Muchá, I.

AU - Venuto, R. C.

PY - 1995

Y1 - 1995

N2 - In this study, we first tested the hypothesis that the previously demonstrated circulatory failure and thrombocytopenia induced by intracaval administration of thromboxane A2 (TxA2) analogues in nonpregnant (NP) rabbits [G. Losonczy, I. Mucha, J. DiPirro, J. Sweeney, G. Brown, J. Brentjens, and R. Venuto. Am. J. Physiol. 265 (Regulatory Integrative Comp. Physiol. 34): R772-R780, 1993] could be avoided if the compounds were given instead into the aortic arch. Conscious New Zealand White rabbits received bolus injections of U-46619 (5-20 μg) through a previously implanted catheter threaded into the aortic arch. Indeed, mean arterial pressure (MAP) rose modestly, and thrombocytopenia did not develop. Next, we compared the blood pressure responses of pregnant (P) rabbits with those of NP rabbits to intra-aortic U-46619 and I-BOP, because they had been found to be resistant to both the hypotensive and platelet aggregatory effects of intracaval U- 46619. Resting blood pressure was lower in P than in NP rabbits (74 ± 3 vs. 95 ± 2 mmHg), but showed a greater increase in response to U-46619. For example, following a 20-μg dose blood pressure rose 20 ± 0.3 mmHg in P vs. 12 ± 2.1 mmHg in NP rabbits (P <0.02). Similar results were obtained with the second TxA2 analogue I-BOP. Pregnancy-induced enhancement of blood pressure elevation may be the consequence of peripheral vasoconstriction, which was not seen in NP rabbits. Thus the actions of TxA2 analogues U- 46619 and I-BOP are markedly influenced by the route of administration. Furthermore, these compounds appear to be the only known vasoconstrictors whose prohypertensive effects are enhanced by normal pregnancy.

AB - In this study, we first tested the hypothesis that the previously demonstrated circulatory failure and thrombocytopenia induced by intracaval administration of thromboxane A2 (TxA2) analogues in nonpregnant (NP) rabbits [G. Losonczy, I. Mucha, J. DiPirro, J. Sweeney, G. Brown, J. Brentjens, and R. Venuto. Am. J. Physiol. 265 (Regulatory Integrative Comp. Physiol. 34): R772-R780, 1993] could be avoided if the compounds were given instead into the aortic arch. Conscious New Zealand White rabbits received bolus injections of U-46619 (5-20 μg) through a previously implanted catheter threaded into the aortic arch. Indeed, mean arterial pressure (MAP) rose modestly, and thrombocytopenia did not develop. Next, we compared the blood pressure responses of pregnant (P) rabbits with those of NP rabbits to intra-aortic U-46619 and I-BOP, because they had been found to be resistant to both the hypotensive and platelet aggregatory effects of intracaval U- 46619. Resting blood pressure was lower in P than in NP rabbits (74 ± 3 vs. 95 ± 2 mmHg), but showed a greater increase in response to U-46619. For example, following a 20-μg dose blood pressure rose 20 ± 0.3 mmHg in P vs. 12 ± 2.1 mmHg in NP rabbits (P <0.02). Similar results were obtained with the second TxA2 analogue I-BOP. Pregnancy-induced enhancement of blood pressure elevation may be the consequence of peripheral vasoconstriction, which was not seen in NP rabbits. Thus the actions of TxA2 analogues U- 46619 and I-BOP are markedly influenced by the route of administration. Furthermore, these compounds appear to be the only known vasoconstrictors whose prohypertensive effects are enhanced by normal pregnancy.

KW - eicosanoids

KW - gestation

KW - systemic hemodynamics

UR - http://www.scopus.com/inward/record.url?scp=0029091949&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029091949&partnerID=8YFLogxK

M3 - Article

C2 - 7573575

AN - SCOPUS:0029091949

VL - 269

JO - American Journal of Physiology

JF - American Journal of Physiology

SN - 0363-6119

IS - 3 38-3

ER -