Effect of a prostacyclin derivative (iloprost) on regional blood flow, sympathetic nerve activity, and baroreceptor reflex in the conscious rat

Helmut Steinberg, Oleg S. Medvedev, Friedrich C. Luft, Thomas Unger

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We have investigated the hemodynamic actions of iloprost, a stable prostacyclin derivative, in conscious, chronically instrumented rats. Given intravenously by 10-min infusions at doses ranging from 0.0375 to 4 μg/min, iloprost lowered mean arterial blood pressure in a dose-dependent and reversible fashion. The effects on blood pressure were accompanied by increases in heart rate (HR); splanchnic nerve activity (SpNA, direct recording); and mesenteric, renal, and hindlimb blood flow (Doppler probes). Doses below the depressor threshold already reduced mesenteric and hindlimb vascular resistance without affecting HR. The reduction of hindlimb resistance outlasted the iloprost infusion period. Chronic sinoaortic deafferentation (SAD) almost abolished the tachycardic reflex responses to intravenous sodium nitroprusside. The reflex increases in SpNA to intravenous iloprost were also largely prevented in SAD animals, but the tachycardic effects of iloprost persisted. In addition, neither β1-adrenoceptor blockade alone nor complete cardiac autonomic blockade prevented the heart rate responses to iloprost. Our results show that iloprost is a potent vasodilator that preferentially reduces hindlimb vascular resistance. Low doses of the drug increase regional blood flow without affecting blood pressure or heart rate. The tachycardic effects at higher doses cannot be explained by baroreceptor reflex (BRR) activation alone; they instead suggest a direct action on the heart. The dissociation between vasodilator and depressor effects at low doses may contribute to the therapeutic benefit of the drug in the treatment of vascular disease.

Original languageEnglish (US)
Pages (from-to)84-89
Number of pages6
JournalJournal of Cardiovascular Pharmacology
Volume11
Issue number1
DOIs
StatePublished - Jan 1 1988
Externally publishedYes

Fingerprint

Iloprost
Baroreflex
Regional Blood Flow
Epoprostenol
Hindlimb
Heart Rate
Vasodilator Agents
Vascular Resistance
Reflex
Arterial Pressure
Splanchnic Nerves
Blood Pressure
Renal Circulation
Nitroprusside
Vascular Diseases
Pharmaceutical Preparations
Adrenergic Receptors
Hemodynamics
Therapeutics

All Science Journal Classification (ASJC) codes

  • Pharmacology
  • Cardiology and Cardiovascular Medicine

Cite this

Effect of a prostacyclin derivative (iloprost) on regional blood flow, sympathetic nerve activity, and baroreceptor reflex in the conscious rat. / Steinberg, Helmut; Medvedev, Oleg S.; Luft, Friedrich C.; Unger, Thomas.

In: Journal of Cardiovascular Pharmacology, Vol. 11, No. 1, 01.01.1988, p. 84-89.

Research output: Contribution to journalArticle

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