Effects of intravenous endothelin on hemodynamics and cardiac contractility in conscious milan normotensive rats

Xiao Ping Yang, Paulo Madeddu, Rosella Micheletti, Elizabeth English, Roberto Rossi, Giuseppe Giacalone, Paula Benatti, Giuseppe Bianchi

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The effects of endothclin-1 (ET-I) on hemodynamic, and cordite contractility were compared with the response, to angiotensin I TAD and phenylephrine (PE) in Milan normotensive rats. Intravenous. intection of (ET-I 10.8 nmol kg) initially decreased mean blood pressure (MBPL). total peripheral resistance (TPR). and dP dt 28 ± 2 34.8 3.2 and 9.4 ± 1.38 p 0.01, respectively, and increased heart rate (HR), cardiac output (CO). and the velocity of mvocordial anterior wall shortening (dl dt). (11.8 2.1 10.4 2.9 and 28.3 8.3 (p 0.05) respectively. These effects were followed by at a sustained increase in NBP and TPR and a decrease in CO. As compared with AI (0.25 nmol kg) and PE: 13 nmol kg). which produced a similar degree of increase in TPR, the reduction in CO induced by EF-I was more prominent 25. 2 by EI-1 vs 14 ± 2 by Al and 14 ± 3'by PE. p 0.05 respectively). Moreover. ET-1 induced a significant decrease in dp dt, shortening fraction (SF). and dL dt 1–6.1 ± 35.0 ± 3.8 and – 38.6 ± 5.5 P 0.01 respectively). Whereas these indexes of left ventricle performance were not affected by either M or PE. Furthermore the reduction in SF induced by ET-I was mainly due to the decrease in myocardial diastolic segment lengh. Suggesting reduction in diastolic filling volume. Together. these finding indicate that, in contrast to the effects AI adn PE the effects of ET-1 on cardtac function depend not only on the increase in afterload, but also on the alteration in either preload or cardiac contractility or both.

Original languageEnglish
Pages (from-to)662-669
Number of pages8
JournalJournal of Cardiovascular Pharmacology
Issue number4
Publication statusPublished - 1991


  • Angiotensin
  • Cardiac output
  • Endothelin
  • Myocardial segment length
  • Phenylephrine
  • Shortening fraction
  • Velocity of shortening

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Pharmacology

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