Figure 4. Cl-currents induced by propofol in dissociated supraoptic nucleus neurons. (A) Representative current traces showing dose-dependent responses to propofol. The holding potential (Vh) was -60 mV. Arrows indicate the time when ramp pulses from -80 to 20 mV (for 200 ms) were applied. (B) The peak amplitude of the propofol-induced currents against the concentrations of propofol. Control represents currents measured in the absence of propofol. At concentrations greater than 10-6M, propofol induced significant currents. Results are the mean +/- SD of nine independent experiments. **Significant (P < 0.01) from control by one-way analysis of variance using the Scheffe F test. (C) Current-voltage (I-V) relations of propofol-induced currents in response to ramp pulses from -80 to 20 mV. The I-V relations of (1)-(4) are obtained by ramp pulses shown in A. The I-V relation of currents induced by 104M gamma-aminobutyric acid is also shown (5). (D) The I-V relations of propofol-induced currents obtained with methansulfonate as the major anion in the pipette. The I-V relations were shifted toward the left (hyperpolarized potentials).