BIX 02565 is a potent inhibitor of ribosomal S6 kinase 2 (RSK2, IC50: 1.1 nM).

RSK2:1.1 nM (cell free), LRRK2:16 nM (cell free), PRKD1:35 nM (cell free)

A monolayer of exponentially growing HLR-CREB cells was prepared and transfected using Effectene with RSK2. Cells were plated into 96-well culture plates, and compounds were added 20 to 24 h after transfection. Luciferase expression (48 h) and activity (5 min) were determined using Steady-Glo per manufacturer's instructions, and results were represented as the percentage luciferase activity relative to the control measured in the absence of inhibitors (percentage of control); the IC50 was fitted to a standard four-parameter logistic equation. Each data point represents an average of triplicate observations [2].

Mean arterial pressure was assessed in conscious, freely moving male Sprague-Dawley rats (n = 6/group) instrumented with telemetry transmitters similar to that described previously. BIX 02565 (30, 100, and 300 mg/kg p.o. QD) was administered as a solution (10 ml/kg) in a 20% hydroxy-propyl-β-cyclodextran vehicle as described previously. Mean arterial pressure was reported from 2 h before (baseline) and 90 h after the first dose; compound was administered at 0, 24, 48, and 72 h. A blood sample was collected from satellite rats (n = 3/group) at 1-h after dose (Tmax) on days 1 and 4 for analysis of plasma drug concentrations by mass spectrometry [2].