Stroke, Vol 24, 1528-1533, Copyright © 1993 by American Heart Association
A Klee, S Vater, GW Schmid-Schonbein and D Seiffge
BACKGROUND AND PURPOSE: Platelet behavior of Sprague Dawley (SD), Wistar
(WI), Wistar-Kyoto (WKY), spontaneously hypertensive (SHR), and
stroke-prone spontaneously hypertensive rats (SHRSP) was studied in vivo to
evaluate the importance of hypertension-related hemostatic disorders.
METHODS: The study was based on the model of stimulus- induced pulmonary
microembolization of labeled platelets. After injection of 51Cr-labeled
homologous platelets into urethane- anesthetized rats, the organ
distribution of the platelets was continuously monitored by gamma
detectors. Count rates of two detectors- -one placed above the animals'
thoraxes (C1), the other above their abdomens (C2)-and the ratio of C1:C2
were calculated. The following platelet activators were applied
intravenously: adenosine diphosphate (ADP; 50 micrograms/kg), collagen (100
micrograms/kg), and thrombin (50 IU/kg). RESULTS: All three substances
caused a reversible pulmonary accumulation of the labeled platelets and
hence an increase in C1/C2 (delta C1/C2%). ADP induced a shift of 75% in
SD, 52% in WI, 32% in WKY, 30% in SHR, and 31% in SHRSP. Thrombin-mediated
shift was 79% in SD, 64% in WI, 58% in WKY, 48% in SHR, and 54% in SHRSP.
Collagen induced a shift of 85% in SD, 96% in WI, 84% in WKY, 56% in SHR,
and 62% in SHRSP. CONCLUSIONS: Because indistinguishable results were
observed in both hypertensive strains, we conclude that impaired platelet
aggregation is not specific for SHRSP. Hence, it may not primarily be
responsible for the increased occurrence of stroke in these animals.
ARTICLES
Evidence from comparative investigations that impaired platelet activation is not specific for stroke-prone spontaneously hypertensive rats
Hoechst AG, Werk Kalle-Albert, Wiesbaden, Germany.
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