Pertussis toxin inhibits VSMC chemotaxis induced by CCL1 and by Lp(a) conditioned medium (LCM). CCL1 and LCM prepared as detailed in the legend for Figure 3 were tested for chemotactic activity using VSMCs pretreated with either pertussis or cholera toxin as described in “Materials and methods.” Pertussis toxin (PT) inhibited VSMC chemotaxis in response to both agonists (*P < .00001), whereas cholera toxin (CT) did not inhibit chemotaxis (NS). These data confirm that Gi-coupled protein receptors are involved in the chemotactic response of VSMCs to CCL1 and LCM. Error bars represent SD.