For proteomic analysis, High-performance liquid chromatography/electrospray mass spectrometry will be employed as a complementary route to discovering differences in protein expression between healthy and traumatized tissue. Following solid-phase extraction of soluble and solubilized proteins, we will optimize conditions for separation of protein peaks detected by UV absorbance and/or total ion current and may employ more than one set of conditions in order to focus on different sets of extracted proteins. We will use high-porosity C-18 reversed-phase columns to separate cytosolic proteins, and C-4 for membrane proteins. Standard methods of ionization, fragmentation, and detection will be used that are consistent with the Shimadzu LCMS-IT-TOF mass spectrometer at the Research Operations Service (ROS).