English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The effect of guanosine 5'-[beta-thio]diphosphate (GDP[beta S]), reported to be an antagonist of GTP at the G-protein-binding site, on human platelet activation was examined. GDP[beta S] (0.3-3 mM) had significant inhibitory effects on platelet aggregation and 5-hydroxytryptamine (5HT) secretion induced by thrombin, collagen, the thromboxane mimetic U46619 and 1,2-dioctanoylglycerol (diC8) in intact platelets, as well as in saponin-permeabilized platelets. Similar inhibitory effects in intact platelets were also observed with ATP (over similar concentration ranges) and GDP and GTP (at 2- and 10-fold higher concentrations respectively). All four nucleotides also inhibited ADP-induced platelet aggregation in indomethacin-treated platelets under conditions where no 5HT secretion occurred. Inhibition of thrombin-induced aggregation and secretion by GDP[beta S] and ATP in intact platelets was accompanied by a reduction in the thrombin-induced rise in intracellular Ca2+ levels and 45 kDa-protein phosphorylation. The results suggest that at least some of the effects of GDP[beta S] may be unrelated to inhibition of G-protein-GTP interaction, but, instead, may be mediated via an extracellular site, common to all the nucleotides tested and perhaps via inhibition of the effects of endogenous/released ADP. The usefulness of GDP[beta S] as a tool in studying G-protein-GTP interactions in platelets is thus questionable.

biochemical journal

Inhibition of agonist-induced platelet aggregation, Ca2+ mobilization and granule secretion by guanosine 5′-[β-thio]diphosphate and GDP in intact platelets. Evidence for an inhibitory mechanism unrelated to the inhibition of G-protein-GTP interaction