The mRNA level of the potassium-chloride cotransporter KCC2 covaries with seizure susceptibility in inferior colliculus of the post-ischemic audiogenic seizure-prone rat

Cardiac arrest and resuscitation were used to induce brain damage and susceptibility to sound-triggered seizures in Sprague–Dawley rats. Glucose preloading was used to vary seizure susceptibility. Because loop diuretics can block these seizures, we investigated changes in KCC2, a potassium-chloride cotransporter, in the inferior colliculus – the origin of the seizures. Using polymerase chain reaction (PCR), we found that collicular KCC2 mRNA levels covaried with seizure susceptibility in these animals. Using quantitative PCR, we found that a fivefold increase in collicular KCC2 mRNA levels was associated with a doubling of seizure incidence. A hypothesis linking KCC2 activity to seizure susceptibility is presented.