Pressor actions of arginine vasopressin in pithed sprague-dawley, wistar-kyoto and spontaneously hypertensive rats before and after treatment with nifedipine or pertussis toxin

Reza Tabrizchi, Christopher R. Triggle

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The pressor actions of arginine vasopressin (AVP) were examined in pithed Sprague-Dawley and Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). Prior to pithing, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were recorded via an intra-arterial catheter from sodium pentobarbital anaesthetized rats. SBP and DBP recorded from SHR were significantly greater than those from Sprague-Dawley and WKY rats. However, after pithing, there were no significant differences between DBP among the various strains. Pertussis toxin pretreatment significantly reduced the prepithing SBP and DBP of the SHR but not Sprague—Dawley or WKY rats. Administration of nifedipine significantly reduced DBP of pithed rats. The dose—diastolic pressure response curves obtained from infusion of AVP in Sprague-Dawley and WKY rats were not significantly different from one another, but the maximal vasopressor responses to AVP in pithed SHR were enhanced. Administration of nifedipine to Sprague-Dawley and WKY rats did not affect the dose-response curve to AVP, but nifedipine administration in SHR led to a significant inhibition of the pressor responses to AVP. Furthermore, pertussis toxin pretreament of rats significantly reduced a component of the AVP pressor effect in SHR but not Sprague-Dawley or WKY rats. We speculate that, in SHR, vasopressin receptors are coupled to a pertussis toxin-sensitive G protein that, in turn, may couple to a dihydropyridine-sensitive calcium channel and also to a pertussis-insensitive G protein that is probably coupled to the phospholipase C/intracellular calcium release process. A component of the elevated blood pressure in SHR is also regulated by a pertussis toxin-sensitive process. However, this toxin does not have a significant effect on the blood pressure of Sprague-Dawley or WKY rats, suggesting that there is a pertussis toxin-sensitive receptor and/or channel which is differentially expresse.

Original languageEnglish
Pages (from-to)813-818
Number of pages6
JournalJournal of Hypertension
Issue number9
Publication statusPublished - Sep 1991



  • Calcium antagonist
  • Pertussis toxin
  • Spontaneously hypertensive rats
  • Vasopressin

ASJC Scopus subject areas

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

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