What is the result of P2Y1 activation at low concentrations of ADP?

The activation of the P2Y1 receptor by low concentrations of ADP leads to a shape change in platelets. When ADP binds to the P2Y1 receptor, which is a G-protein coupled receptor, it initiates a cascade of intracellular signaling that results in the change in morphology of the platelet. This shape change is a crucial initial response in the process of platelet activation, which prepares the platelets for further aggregation.

This transformation alters the surface area and the interaction of platelets with the endothelium and other platelets, creating the necessary conditions for subsequent steps in hemostasis. It is important to note that while other processes like aggregation and degranulation can occur at higher concentrations of ADP, the primary effect of P2Y1 activation at low concentrations is the shape change that stimulates further platelet responses in the hemostatic process.