Inhibition of indium-111 platelet accretion onto venous thrombi in dogs by prostacyclin
The known platelet anti-aggregant effects of prostacyclin (epoprostenol) suggest that it may have therapeutic potential in conditions in which the platelet plays a pathophysiological role. The growth of venous thrombi is one such condition. We have attempted to determine, in a canine model of fresh venous thrombosis, whether prostacyclin infusion inhibits platelet accretion in vivo and how this in vivo event related to hemodynamic and in vitro platelet anti-aggregant effects. Gamma camera imaging over thrombi for accretion of indium-111-labeled platelets disclosed that prostacyclin, at an infusion rate of 50 ng/kg per min, inhibited platelet accretion in vivo and resulted in a 95 +/- 4% decrease in in vitro adenosine diphosphate-induced platelet aggregation, and a decrease in mean arterial pressure to 86 +/- 4% of pre-infusion values. Step-wise decrements of prostacyclin infusion demonstrated that platelet accretion occurred in vivo at infusion rates of approximately 10-20 ng/kg per min and correlated with an in vitro adenosine diphosphate-induced aggregation of 54 +/- 13% of control values. Thus, prostacyclin, in a dose that causes only a mild decrease in systemic pressure, can completely inhibit platelet uptake onto fresh venous thrombi in the dog, and this inhibition correlates closely with in vitro adenosine diphosphate-induced platelet aggregation. The potential therapeutic implications of these findings are discussed.
- Research Organization:
- Univ. of California, San Diego
- OSTI ID:
- 7016172
- Journal Information:
- Circ. Res.; (United States), Journal Name: Circ. Res.; (United States) Vol. 53:6; ISSN CIRUA
- Country of Publication:
- United States
- Language:
- English
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62 RADIOLOGY AND NUCLEAR MEDICINE
AGGLOMERATION
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD PLATELETS
BLOOD VESSELS
BODY
BODY FLUIDS
CARDIOVASCULAR SYSTEM
COUNTING TECHNIQUES
DAYS LIVING RADIOISOTOPES
DIAGNOSTIC TECHNIQUES
DOGS
ELECTRON CAPTURE RADIOISOTOPES
EMBOLI
IN VITRO
IN VIVO
INDIUM 111
INDIUM ISOTOPES
INHIBITION
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MATERIALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ORGANS
PROSTAGLANDINS
RADIOISOTOPE SCANNING
RADIOISOTOPES
SCINTISCANNING
VERTEBRATES