Effects of photolysable 2-azido analogues of adenosine, AMP and ADP on human platelets.

The aggregating effect of ADP on human platelets and the inhibiting effect of adenosine are apparently mediated by different receptors on the cells’ outer membranes. Photolysable azido-analogues of adenosine, AMP and ADP have been prepared so tha t the receptors for them can be labelled. 2-Azidoadenosine inhibited platelet aggregation by ADP more than adenosine itself and increased platelet cAMP as effectively as did adenosine or 2-chloroadenosine. 2-Azido-AMP inhibited aggregation much more effectively than AMP itself or than 2-chloro-AMP. 2-Azido-ADP was about five times more potent than ADP in causing aggregation. All these 2-azido derivatives were photolysable by irradiation at 365 nm which does not affect platelet functions.