Enhanced vascular effects of the Ca2+ channel agonist Bay K 8644 in pregnant rabbits

Rocco Venuto, Gail Brown, Marion Schoenl, G. Losonczy

Research output: Contribution to journalArticle

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Abstract

Hemodynamic studies were performed to determine if blunting of vascular pressor responsiveness to vasoconstrictors during pregnancy may be due to impaired L-type voltage-dependent calcium channels (L-VDCC). Bay K 8644 (BAY), an L-VDCC agonist, was infused in pregnant and nonpregnant anesthetized rabbits (10, 20, 40, and 60 μg/kg) and pregnant and nonpregnant conscious, chronically instrumented (conscious) rabbits (10, 25, and 50 μg/kg). BAY infusions resulted in greater elevation of mean arterial pressure in both anesthetized pregnant (n = 6) vs. nonpregnant (n = 6) (P <0.05) and conscious pregnant (n = 10) vs. nonpregnant (n = 10) rabbits (P <0.05). Fractional increase over baseline of total peripheral resistance index was greater in pregnant (36 ± 5 to 78 ± 14%) vs. nonpregnant rabbits (14 ± 4 to 52 ± 6%) (P <0.02). Cardiac output index did not differ. There was a single high-affinity L-VDCC antagonist aortic binding site with similar number and affinity in pregnant (n = 7) and nonpregnant (n = 7) rabbits. In conclusion, stimulation of L-VDCC induces greater pressor responses in pregnant rabbits with heightened peripheral vasoconstriction. This does not appear to be due to a change in L-VDCC receptor parameters.

Original languageEnglish
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume282
Issue number4 51-4
Publication statusPublished - 2002

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3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
L-Type Calcium Channels
Blood Vessels
Rabbits
Calcium Channel Agonists
Calcium-Sensing Receptors
Calcium Channel Blockers
Vasoconstrictor Agents
Vasoconstriction
Cardiac Output
Vascular Resistance
Arterial Pressure
Hemodynamics
Binding Sites
Pregnancy

Keywords

  • Blood pressure
  • Calcium channels
  • Nifedipine
  • Vascular reactivity

ASJC Scopus subject areas

  • Physiology

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Enhanced vascular effects of the Ca2+ channel agonist Bay K 8644 in pregnant rabbits. / Venuto, Rocco; Brown, Gail; Schoenl, Marion; Losonczy, G.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 282, No. 4 51-4, 2002.

Research output: Contribution to journalArticle

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