The effects of adrenergic stimulation on platelet aggregation (platelet aggregation ratio; PAR), β-thromboglobulin (β-TG) release and plasma thromboxane B2 (TxB2) levels were investigated in 25 healthy young volunteers. Adrenergic stimulation induced by cold application was checked by evaluating the changes in the calculated vascular resistance in the forearm. A prompt increase in platelet aggregates and plasma β-TG and TxB2 concentrations was observed after adrenergic stimulation. PAR changed from resting values of 0.97 ± 0.05 to 0.75 ± 0.08 (p2 plasma levels changed from 32.09 ± 19.64 to 135.48 ± 37.97 ng/ml (p <0.001) and TxB2 levels, but not PAR and β-TG concentration came back to the resting values at the end of the observation period (10 min). Aspirin, as the lysine acetylsalicylate equivalent to 5 mg/kg i.v. of acetylsalicylic acid, although able to completely inhibit platelet cyclooxygenase failed to inhibit the plasma TxB2 increase induced by adrenergic stimulation. This strongly suggests that the increase in plasma TxB2 following adrenergic stimulation is of extraplatelet origin. Also β-TG and PAR changes were not affected by aspirin administration.
|Number of pages||9|
|Publication status||Published - 1982|
ASJC Scopus subject areas