Fig. 4: Spermine has no effect on diazepam potentiation of GABA_ARs.

a Average concentration-response curve of diazepam potentiation of GABA currents, using data from 4 subjects, 4–5 oocytes each. Mean ± s.e.m. The current elicited by GABA’s EC₂₅ in each oocyte was defined as zero in the plot. The average EC₅₀ for all subjects was 275 ± 66 nM (mean ± s.e.m; n = 17). The individual EC₅₀ for each subject was: S1 = 253 ± 11 nM (n = 4), S2 = 273 ± 16 nM (n = 4), S3 = 159 ± 55 nM (n = 4) and S4 = 670 ± 121 nM (n = 5). Higher concentrations of diazepam reduced the efficacy of the potentiation. b Representative traces of currents elicited by GABA’s EC₂₅ co-applied with 100 nM diazepam before and in the presence of 100 µM spermine. c The plot shows no change of the normalized maximal current responses elicited by GABA’s EC₂₅ plus 100 nM diazepam and 100 µM spermine (+) compared to those without it (−) (n = 6 oocytes/3 subjects)