Role of Aquaporins in the Formation and Resolution of Brain Edema

In this chapter, we describe the role of water channel proteins, aquaporins (AQPs), in brain edema formation. The recent knowledge on the three main AQPs expressed in the brain (AQP1, AQP4, and AQP9) is summarized; however, AQP4 is the most studied in the central nervous system. Thus, AQPs, and in particular AQP4, have important roles both in the formation and resolution of edema after brain injury. The dual, complex function of these water channel proteins makes them an excellent therapeutic target. To date, no specific therapeutic agents have been developed to either inhibit or enhance water flux through these channels. However, experimental results strongly underline the importance of this topic for future investigation.