Actions of histamine and serotonin on cultured EC. (A) H3 thymidine incorporation. (B,C) Transwell and scratch monolayer migration. (D) Tube formation. Serum-starved HUVEC, with or without pretreatment with indicated inhibitors or antagonists, were stimulated with histamine (10 μM), serotonin (1 μM), or VEGF-A¹⁶⁵ (10 ng/mL), as described in “Methods.” Results are summarized in Table 1. (A) ³H thymidine incorporation assay (n = 4; data are representative of 3 independent experiments). (B) Transwell migration (n = 4; data are representative of 3 independent experiments). (C) Scratch monolayer migration (total n = 20 from three independent experiments). (D) Tube formation (n = 20 from 3 independent experiments). *P < .05; **P < .01; ***P < .001. Tukey-Kramer multiple comparisons test (A, B, D); Kruskal-Wallis test with Dunn multiple comparison (C).