BMP7 evokes rapid PI3K-dependent stimulation of Akt phosphorylation in dI neurons. (A) Dissociated dI neurons pretreated with or without 50 μM LY and incubated with 50 ng/ml BMP7 for 0, 2, 5 or 15 minutes. Western blots of whole cell lysates probed with phospho-specific α-Akt or α-Smad1/5/8, then α-total cellular Akt protein (to normalize the pAkt signals). (B, C) pAkt (B) and pSmad1/5/8 (C) levels in the same dI neurons in response to 50 ng/ml BMP7 with or without LY, at 15 minutes. Percentage of control for each condition (mean ± SEM)): for pAkt, BMP7 - LY = 179 ± 6% and BMP7 + LY = 67 ± 18% (n = 2); for pSmad1/5/8, BMP7 - LY = 913 ± 175% and BMP7 + LY = 1,143 ± 448% (n = 2). Student's t-tests: BMP7-evoked pAkt in dI neurons with LY differs significantly from pAkt without LY (BMP7 - LY versus BMP7 + LY, *P < 0.05). BMP7-induced pSmad1/5/8 levels did not differ in dI neurons with or without LY (BMP7 - LY versus BMP7 + LY, P = 0.6798).