SUB-CELLULAR LOCALIZATION OF IN-111 IN HUMAN AND RABBIT PLATELETS

  • 1 January 1982
    • journal article
    • research article
    • Vol. 59  (2) , 351-359
Abstract
To examine the subcellular distribution of 111In in 111In-oxine-labeled human and rabbit platelets, a hypothetical grain technique of EM autoradiography analysis was used. In the rabbit 111In was concentrated within the platelet dense bodies, particularly when the platelets were labeled in a plasma-free system. Under comparable conditions of labeling, human platelets appeared to accumulate almost all the radiolabel within the cytosol. Using inhibitors of 5-hydroxytryptamine (5-HT) uptake, i.e., cloimipramine, ouabain, sodium fluoride, p-chloromercuribenzoate and reserpine, no active uptake process could be demonstrated in either species. Both collagen and thrombin were able to cause dose-dependent release of radioactivity from the labeled rabbit platelets only. In the case of collagen, this mimicked endogenous 5-HT [5-hydroxytryptamine] release and was inhibited by indomethacin. These results and their implications are discussed.