Figure 1.

Platelet shape change induced by mox-LDL is mediated by activation of the LPA receptor. The decrease of light transmission and the disappearance of oscillations are indicative of shape change (13). (a) Homologous desensitization of shape change to mox-LDL (0.2 mg/ml). Subsequent addition of ADP (2 μM) and the peptide YFLLRNP (300 μM), a partial thrombin-receptor agonist (13), still induces shape change. (b) LPA (0.5 μM) desensitizes platelets to subsequent stimulation by mox-LDL (0.2 mg/ml) and vice versa. (c) Platelets were preincubated for 5 min with 0.1% ethanol (E) or 10 μM the specific LPA-receptor antagonist N-palmitoyl tyrosine phosphoric acid (NPTyrPA) dissolved in ethanol (N) before stimulation with LPA, mox-LDL, ADP, YFLLRNP, or PAF (100 nM). (d) Comparison of shape change induced by nat-LDL (n-LDL), mox-LDL, and mm-LDL (0.2 mg/ml each). Tracings shown are representative of 15–20 experiments that gave similar results.