The Effect of Oral Contraceptives on Platelet Noradrenaline and 5-Hydroxytryptamine Receptors and Aggregation
Noradrenaline (NA) and 5-hydroxytryptamine (5HT) cause platelet aggregation in vitro, and they enhance aggregation produced by ADP (Mills & Roberts, 1967), collagen and thrombin (Yu & Latour, 1977). There is evidence that platelet membranes possess receptor sites for NA and 5HT. This evidence comes both from functional studies on platelet aggregation and uptake, and from results of radioligand binding techniques which are being used increasingly to demonstrate receptor sites for hormones, neurotransmitters and drugs in various tissues (Tell, Haour & Saez, 1978). The latter technique may enable characteristics of the molecular site of action of a hormone or drug to be examined in some detail and provides a new method for studying aspects of hormone and drug action clinically. Alterations in receptor characteristics have been noted in a number of human disorders (Bar & Roth, 1977; Kaywin, McDonough, Insel & Shattil, 1978).
KeywordsNoradrenaline Progesterone Oestradiol Adrena Line Thrombin
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