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Updated: Jun 17, 2026

Study of the Functions and Activities of Neuronal K-Cl Co-Transporter KCC2 Using Western Blotting
Published on: December 9, 2022
Downregulation of potassium chloride cotransporter KCC2 after transient focal cerebral ischemia
Nadine Jaenisch1, Otto W Witte, Christiane Frahm
1Hans-Berger Clinic for Neurology, Friedrich-Schiller University, Erlanger Allee 101, 07747 Jena, Germany. christiane.frahm@med.uni-jena.de
Background And Purpose:
The potassium chloride cotransporter 2 (KCC2) is the main neuronal chloride extruder in the adult nervous system. Therefore, KCC2 is responsible for an inwardly directed electrochemical gradient of chloride that leads to hyperpolarizing GABA-mediated responses. Under some pathophysiological conditions, GABA has been reported to be depolarizing because of a downregulation of KCC2. This is the first study to our knowledge analyzing the expression of KCC2 after a focal cerebral ischemia.
Methods:
Mild and severe ischemia were induced in rats by a transient occlusion of the middle cerebral artery for 30 and 120 minutes, respectively. KCC2 mRNA and protein expression were studied in the ischemic hemisphere after different reperfusion times (2 hour, 1 day, 7 days, 30 days, 168 days) by using quantitative polymerase chain reaction, Western blotting, and immunohistological staining.
Results:
We found a substantial decrease of KCC2 mRNA and protein levels in the ischemic hemisphere, with a stronger downregulation of KCC2 after severe vs mild ischemia. Long-term surviving cells expressing KCC2 could be detected in the infarct core. These cells were identified as GABAergic interneurons mainly expressing parvalbumin.
Conclusions:
Our study revealed a substantial neuron-specific downregulation of KCC2 after focal cerebral ischemia.
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