An Evaluation of Cation-Chloride Cotransporters NKCC1 and KCC2 in Carbamazepine-Resistant Rats.

Approximately one-third of epileptic patients do not respond adequately to drug therapy, leading to the development of drug-resistant epilepsy. Given the established role of dysregulated expression of two cation-chloride cotransporter proteins, NKCC1 and KCC2, in susceptibility to convulsion generation and epilepsy development, the present study evaluates the anticonvulsant potential of bumetanide (BUM, 10 mg/kg, i.p.) and probenecid (PROB, 50 mg/kg, i.p.), the potential of adenosine receptor activation (NECA, 1 mg/kg, i.p.) to modify the anticonvulsant efficacy of BUM, and the changes in NKCC1 and KCC2 protein expression levels in carbamazepine (CBZ)-resistant animals. In the window-pentylenetetrazole (PTZ) kindling model, male Wistar rats that undergo full kindling develop CBZ-resistance. The combination of BUM + PROB appears to have an anticonvulsant effect on CBZ-resistant convulsions, while alterations in the protein levels of the NKCC1 and KCC2 cotransporters are observed in CBZ-resistant animals. Despite the absence of therapeutic efficacy in managing convulsions through adenosine receptor activation (BUM + NECA), the activation of adenosine receptors exhibits the capacity to modulate the levels of the NKCC1 protein in the hippocampus of CBZ-resistant animals. This effect provides the initial evidence for a new therapeutic role of adenosine receptors in regulating the pathological levels of NKCC1 in drug-resistant epilepsy.