Acute pressor actions of ouabain do not enhance the actions of phenylephrine or norepinephrine in anesthetized rats.

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  • Author(s): Barker LA;Barker LA; Rossoni LV; Vassallo DV
  • Source:
    Journal of cardiovascular pharmacology [J Cardiovasc Pharmacol] 2001 Mar; Vol. 37 (3), pp. 339-48.
  • Publication Type:
    Journal Article; Research Support, Non-U.S. Gov't
  • Language:
    English
  • Additional Information
    • Source:
      Publisher: Lippincott Williams & Wilkins Country of Publication: United States NLM ID: 7902492 Publication Model: Print Cited Medium: Print ISSN: 0160-2446 (Print) Linking ISSN: 01602446 NLM ISO Abbreviation: J Cardiovasc Pharmacol Subsets: MEDLINE
    • Publication Information:
      Publication: Hagerstown, MD : Lippincott Williams & Wilkins
      Original Publication: New York, Raven Press.
    • Subject Terms:
      Blood Pressure/*drug effects ; Enzyme Inhibitors/*pharmacology ; Norepinephrine/*pharmacology ; Ouabain/*pharmacology ; Phenylephrine/*pharmacology; Angiotensin II/pharmacology ; Animals ; Dose-Response Relationship, Drug ; Male ; NG-Nitroarginine Methyl Ester/pharmacology ; Phentolamine/pharmacology ; Rats ; Rats, Wistar
    • Abstract:
      The inhibition of high-affinity isoforms of the Na+,K+-ATPase by nanomolar levels of ouabain has been proposed to enhance the actions of vasoconstrictor agents that act via a Ca+2-dependent mechanism. The present study tested this hypothesis by evaluating the effects of ouabain (6 and 18 microg/kg, i.v.) on the vasopressor actions of phenylephrine and norepinephrine in anesthetized, reflex-blocked rats. In separate groups of animals, dose-response curves for increases in diastolic pressure produced by phenylephrine were generated after the administration of saline (control), ouabain (18 microg/kg), L-omega-N-nitro arginine methyl ester (L-NAME, 3 micromol/kg) and angiotensin II (15 ng/kg per min). Treatment with ouabain (18 microg/kg) produced an increase in diastolic pressure of 19+/-3 mm Hg but did not significantly alter the potency or maximal response produced by phenylephrine. In contrast, treatment with angiotensin II and L-NAME, agents known to enhance the actions of alpha-adrenoceptor agonists, increased the potency of phenylephrine. In animals in which the pressor actions of norepinephrine were evaluated before and after the administration of ouabain (6 microg/kg), ouabain did not alter the pressor response to norepinephrine. Blockade of alpha-adrenoceptors with phentolamine was found to attenuate as well as partially reverse the increase in diastolic pressure produced by ouabain. These observations suggest that ouabain produces a pressor response by actions on sympathetic nerve endings as well as on vascular smooth muscle and that these actions do not alter the sensitivity to phenylephrine or norepinephrine.
    • Accession Number:
      0 (Enzyme Inhibitors)
      11128-99-7 (Angiotensin II)
      1WS297W6MV (Phenylephrine)
      5ACL011P69 (Ouabain)
      V55S2QJN2X (NG-Nitroarginine Methyl Ester)
      X4W3ENH1CV (Norepinephrine)
      Z468598HBV (Phentolamine)
    • Publication Date:
      Date Created: 20010313 Date Completed: 20010524 Latest Revision: 20190724
    • Publication Date:
      20231215
    • Accession Number:
      10.1097/00005344-200103000-00013
    • Accession Number:
      11243425