Platelet thromboxane A2 receptors in habitual smokers.
Cigarette smoking is a major risk factor for cardiovascular disease but its effect on platelet aggregability and particularly on TxA2 platelet metabolism is controversial. In present study TxA2 platelet receptors of 8 male clinically healthy habitual smokers (more than 20 cig./day) aged 30-55 (44 +/- 6 years) and of 9 age matched healthy controls were evaluated. Platelet TxA2 receptors were investigated by a radioligand binding method employing 125I-PTA-OH, a radio-iodinated hydroxy derivative of the 13-azapinane thromboxane antagonist (ONO 11120). Binding studies evidentiated a single class of specific high affinity receptors for the TxA2 analogue. In non smokers 990 + 220 receptors/platelet (rec/plt) with a dissociation constant (kd) of 22 +/- 11 nM were found. Smokers had a significantly larger number of TxA2 platelet receptors (1268 +/- 190 rec/plt p less than 0.01). No differences in the receptor affinity was found (23 +/- 6 nM, ns). Those changes could contribute to the high responsiveness of platelet from smokers to external aggregating stimuli.
Modesti
P A
PA
Clinica Medica I, University of Florence, Italy.
Abbate
R
R
Gensini
G F
GF
Colella
A
A
Neri Serneri
G G
GG
D000328:Adult; D001667:Binding, Competitive; D001792:Blood Platelets / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation; D011982:Receptors, Prostaglandin / Q000032:analysis*; D017482:Receptors, Thromboxane; D012907:Smoking / Q000097:blood*; D013928:Thromboxane A2 / Q000097:blood*
D011982:Receptors, Prostaglandin; D017482:Receptors, Thromboxane; D013928:Thromboxane A2