TNF alpha in cerebrospinal fluid of meningitis patients reduces astrocytes membrane potential

During inflammatory CNS diseases cytokines are released into the cerebrospinal fluid (CSF). Astrocytes which are target cells for cytokines also contribute importantly to undisturbed neuronal function e.g. by maintaining local ion homeostasis. The effects of CSF from patients with septic (CSF-SM) and aseptic (CSF-ASM) meningitis on electrophysiological membrane properties of cultured rat cortical astrocytes were investigated. Astrocytes significantly depolarized from a membrane potential of -75.6 +/- 2.3 to -47.4 +/- 6.2 mV in CSF-SM (n = 8). 12 of 18 CSF-ASM also induced a depolarization. The depolarization of astrocytes was inhibited by a neutralizing anti-TNF alpha antibody, indicating that the cytokine TNF alpha initiates the depolarization.