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. 2002 Sep;137(1):87–97. doi: 10.1038/sj.bjp.0704832

Figure 7.

Figure 7

Action of cortisol on recombinant hKv1.3 potassium channels. (A) Illustration of the voltage protocol used; cells were held at −80 mV and stepped to command potentials in the range of −120 mV to +70 mV, in 10 mV increments. Up to 20 s was allowed between each pulse for recovery of inactivation. (B) A family of hKv1.3 potassium currents recorded under control conditions. (C) A family of hKv1.3 potassium currents recorded in the presence of 10 μM cortisol. (D) Mean normalized Boltzmann curves from a number of experiments similar to those shown in (B) & (C). (E) Shift in midpoint parameter was statistically significant at both 1 μM and 10 μM, and greatest when cortisol was included both in the bath, and in the pipette (indicated by ‘10 μM*'). Note that 10 μM mifepristone, applied in conjunction with cortisol (indicated by ‘+MIF') failed to inhibit the midpoint shift by cortisol. Control: V1/2 −20.6±1.5 mV, k 5.7±0.6 mV, maximum 4.5±0.9 nS (n=14). 0.01 μM cortisol: V1/2 −21.1±1.9 mV, k 2.9±1.4 mV, maximum 0.9±0.1 nS (n=4). 0.1 μM cortisol: V1/2 −16.4±3.0 mV, k 5.8±1.0 mV, maximum 2.5±0.3 nS (n=6). 1 μM cortisol: V1/2 −15.0±3.0 mV (P<0.05), k 5.8±1.0 mV, maximum 3.0±0.6 nS (n=7). 10 μM cortisol: V1/2 −12.9±2.3 mV (P<0.05), k 9.4±1.7 mV, maximum 8.0±1.7 nS (n=12). 10 μM cortisol (bath+pipette): V1/2 −8.3±5.6 mV (P<0.05), k 11.2±6.3 mV, maximum 5.5±1.3 nS (n=4). 10 μM cortisol +10 μM mifepristone (bath+pipette): V1/2 −7.4±5.4 mV (P<0.05 compared to control), k 10.7±1.7 mV, maximum 7.1±3.6 nS (n=3). 24°C Pipette solution III, bath solution VI (Table 1).