Abstract
Tolazoline (TZ), an imidazoline compound with vasodilatory and histaminic properties, is used in the therapy of neonatal persistent pulmonary hypertension (PPH). Inhibition of thromboxane A2 (TBX-A) synthesis by TZ has been reported. The in-vitro effects of TZ on platelet aggregation were studied. Platelet rich plasma obtained from 6 healthy adults and from cord blood samples of 6 healthy term infants was incubated with TZ and aggregated with ADP (10μM). At increasing concentrations of TZ, decreases in maximal aggregation occurred, followed by disaggregation (mean±SEM):
The relationship between TZ concentration and both maximal and 10-minute aggregation was linear up to 103 μg/ml (r≥0.88). The inhibition of primary aggregation at the highest TZ concentrations is inconsistent with TBX-A inhibition alone. Preliminary data, using a radioimmunoassay, suggest an increase in platelet cyclic AMP when incubated with TZ, perhaps mediated by hist-amine receptors. In-vivo inhibition of platelet aggregation and TBX-A release by TZ may be benefical in some forms of PPH.
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Courtney, J., Kenal, K., Garcia-Prats, J. et al. 357 TOLAZOLINE INHIBITION OF PLATELET AGGREGATION. Pediatr Res 19, 170 (1985). https://doi.org/10.1203/00006450-198504000-00387
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DOI: https://doi.org/10.1203/00006450-198504000-00387