Figure 8.

Cyclodextrins demonstrate different factors governing time course of potentiation vs inhibition by steroids. (a1) 3α5αP (0.3 μM) potentiated the response to 0.5 μM GABA. Removal of the steroid produced a slow relaxation (arrow) back towards the original GABA response when GABA alone was applied. (a2) When γ-cyclodextrin (0.5 mM) was included in the GABA solution upon steroid removal, the relaxation (arrow) was accelerated. (b1 and 2) When PS (5 μM) was used to inhibit the response to 2 μM GABA, γ-cyclodextrin (0.5 mM) had no effect on the recovery time course (arrows) of PS offset. (c and d) Summary of the effect of γ-cyclodextrin on the offset τ for potentiation (c, n=11) and inhibition (d, n=5) from experiments like those shown in (a) and (b), respectively. Asterisk indicates P<0.05. In (d), there was no significant difference between the offset τ for inhibition (paired t-test).