Discussion

Potassium-chloride transporter member 5 (KCC2) is one of nine cation-chloride cotransporters (CCCs) encoded by the SLC12 family of genes, and is the only CCC transporter preferentially expressed in neurons. KCC2 plays a critical role in the correct functioning of the CNS where it is pivotal in maintaining neuronal intracellular Cl− concentration ([Cl−]i). KCC2 is involved in the control of numerous neuronal processes and its impaired activity has been identified in epilepsy, neuropathic pain and spasticity following spinal cord injury. This suggests that positive modulators of the activity of expression of KCC2 may provide effective therapy for neuronal conditions arising from defects in KCC2 functionality.
The FLIPR® Potassium Assay Kit contains a novel, highly-sensitive thallium (Tl+) indicator dye that produces bright fluorescence upon binding to Tl+ introduced through potassium channels. The intensity of the signal is proportional to the number of open potassium channels on the cells; therefore it acts as a surrogate indicator of potassium ion channel activity. The kit also employs Molecular Devices proprietary masking dye to reduce background fluorescence resulting in an improved signal/background ratio. As Tl+ is also transported by cation–chloride cotransporters, we show in this poster that the FLIPR Potassium Assay Kit can be used to easily assess the effect of compounds on KCC2 activity by measuring the initial rate of KCC2-mediated Tl+ transport/influx.