Pressure-independent cardiac effects of angiotensin II in pigs.

• BACKGROUND: Angiotensin II (Ang II) is a potent vasoconstrictor with an important role in the development of cardiovascular disease. Earlier results have shown a positive acute inotropic effect of Ang II in anaesthetized pigs together with significant vasoconstriction. This investigation was designed to study cardiac effects of Ang II, when blood pressure was maintained constant by experimental means. METHODS: Ang II (200 microg h(-1)) was infused in anaesthetized pigs (n = 10) at two different arterial blood pressures, the first determined by the effects of Ang II alone, and the second maintained at baseline blood pressure with nitroprusside. Cardiac systolic and diastolic function was evaluated by analysis of left ventricular pressure-volume relationships. RESULTS: Heart rate, end-systolic elastance (Ees) and pre-load adjusted maximal power (PWRmax EDV(-2)) increased at both blood pressure levels, although less when blood pressure was kept constant with nitroprusside. The time constant for isovolumetric relaxation (tau(1/2)) was prolonged with Ang II alone and shortened with Ang II infused together with nitroprusside. CONCLUSION: Ang II infusion in the pig has inotropic and chronotropic properties independent of arterial blood pressure levels, although the effects seem to be blunted by pharmacological actions of the nitric oxide donor nitroprusside.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Anestesi och intensivvård (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Anesthesiology and Intensive Care (hsv//eng)

Nyckelord

Angiotensin II

administration & dosage

pharmacology

Animals

Blood Pressure

drug effects

physiology

Diastole

drug effects

physiology

Female

Heart

drug effects

physiology

Heart Rate

drug effects

physiology

Infusions

Intravenous

Nitric Oxide Donors

pharmacology

Nitroprusside

pharmacology

Swine

Systole

drug effects

physiology

Vasoconstrictor Agents

administration & dosage

pharmacology

Ventricular Function

Left

drug effects

physiology

Angiotensin amide

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)