Figure 4

Rotenone-induced I_AHP alterations are independent of a direct rotenone effect, oxidative modulation, altered transcription and Ca²⁺ sensitivity. (a) Representative I_AHP recording of a LC neuron before (black) and 5 min after 1 µM rotenone was washed in (red). (b,c) Acute rotenone exposure did not alter I_AHP current density (n = 8) (b) or decay time (n = 6) (c). (d) Representative I_AHP recording of a LC neuron before (black) and 5 min after 100 µM H₂O₂ was washed in (purple). (e,f) Wash-in of 100 µM H₂O₂ did not alter I_AHP peak current density (e) or current kinetic (f) within 5 min of wash-in (n = 5). (g) Relative expression (rE) levels of SK1, SK2 and SK3 channel subunits normalized to GAPDH. For expression analysis, LC neurons were collected out of acute brainstem slices (2 h incubation in ACSF (control) or 2 h incubation in 1 µM rotenone). (h) Representative AHP currents in LC neurons of control slices and slices after 2 h pre-incubation with 1 µM rotenone using high concentrations (3 µM) of free Ca²⁺ in the pipette solution to achieve a full SK channel activation. (i,j) Use of high [Ca²⁺]_i did not restore the rotenone-induced reduction of I_AHP current density (n = 7) (i) or current kinetic (n = 5) (j). Box plots display median and 25/75 percentile, whiskers indicate outliers. Rest of the data are represented as mean ± SEM and also as individual data points. *p < 0.05. [(b,c) Mann–Whitney-U test vs. control. (e,f,g,i): unpaired Student’s t-test vs. control. (j): Welch’s t-test vs. control].