Tetanic stimulation reveals slow inward currents in the astrocytes (aSICs). (A) Currents recorded from astrocytes in response to midline stimulation with 10 pulses at 1 Hz (top), 20 pulses at 10 Hz (middle), and 20 pulses at 100 Hz (bottom). (B) Currents recorded in response to midline stimulation with 20 pulses at 100 Hz. Overlay of three consecutive records from the same cell. Inhibition of glutamate transporters with TBOA (200 µM) results in an increase of the current as compared with control. Application of TBOA (200 µM) and CNQX (20 µM) results in a reduction of the current to almost control value. (C) Summary of the current amplitudes and the decay times of the current induced by 20 pulses at 100 Hz under control conditions, under TBOA and under TBOA together with CNQX (n = 21). Data are the mean ± SEM. Asterisks represent significant difference (**, P = 0.002).