“…In the CP epithelium, the Na ϩ ,K ϩ -ATPase is the driving force of the active fluid secretion and is furthermore a major player of various active transport properties including transport of phenol red from apical to basolateral compartment. Disturbance of Na ϩ ,K ϩ -ATPase function might result from an inhibition of the Na ϩ ,K ϩ -ATPase activity, which has been described in neuroblastoma cells or liver tissue by Mn before (45,46), but might also be due ϩ -ATPase has also been reported to be inhibited by ROS in primary cultures (47), and it is generally known that Mn overexposure induces a transient increase in the cellular ROS level of brain cells (48,49). Additionally, chronic Mn exposure might alter systematic homeostasis of calcium, leading to a further impairment of Na ϩ ,K ϩ -ATPase function (14,50).…”