Skip to main content
. 2016 Sep 22;10:434. doi: 10.3389/fnins.2016.00434

Figure 5.

Figure 5

Cholinergic and GABAergic antagonists reduce toluene-induced excitation, but have no effect on excitation produced by ethanol. (A) Ratemeter: Firing rate over 5 s intervals is represented by the height of the vertical bars; duration of drug application is shown by the horizontal bars. Ethanol (EtOH, 80 mM), toluene (400 μM) and nicotine (500 nM) were tested before and in the presence of mecamylamine (1 μM). All three drugs produced excitation in the absence of mecamylamine, but in the presence of mecamylamine, there was a reduction in the excitation produced by nicotine and toluene, with no diminution of the ethanol-induced excitation. Despite the reduction in toluene-induced excitation by mecamylamine in this recording, there was no significant effect of mecamylamine on toluene excitation in the population of responses studied overall. (B) Bars representing the mean responses to ethanol, toluene, and nicotine in the absence (gray bars) and presence (red bars) from the pool of experiments similar to the one depicted in (A). Due to the variation in responses in the presence of mecamylamine, individual responses in the absence (round symbols) and presence (square symbols) are shown superimposed on the bars. Mecamylamine significantly reduced the excitation produced by nicotine but not that produced by toluene or ethanol. (C) Toluene (400 or 800 μM) was tested before (gray bars) and after the addition of 5 μM atropine to the superfusion medium (red bars). In the presence of atropine, the effects of 800 μM toluene were significantly reduced [two-way ANOVA, F(1, 3) = 20.74, P < 0.02, n = 4]. (D) The effects of ethanol (80 mM; gray bars) and toluene (400–800 μM; red bars) were assessed before and after addition of the GABAA antagonist bicuculline (10 μM) and GABAB antagonist CGP35348 (10 μM) to the superfusion medium. Ethanol-induced excitation was not significantly altered by the GABA antagonists, but the excitation produced by toluene was significantly reduced [*P < 0.05, two-way ANOVA, F(1, 13) = 10.44, P < 0.01, n = 14].