Article Figures & Data
Figures
- Figure 1.
mGluR-dependent facilitation of AP-evoked Ca2+ signals is augmented after withdrawal from repeated ethanol exposure. A, Example traces of IK(Ca) illustrating the effects of DHPG (3 μm) on IK(Ca) in cells from saline- and ethanol-treated mice (1 d withdrawal). B, Summary bar graph demonstrating that in vivo ethanol exposure augmented DHPG-induced facilitation of IK(Ca) (naive group, 7 cells from 4 mice; saline group, 10 cells from 5 mice; ethanol group, 14 cells from 8 mice; F(2,28) = 6.25, p < 0.01, one-way ANOVA). *p < 0.05 versus naive and saline groups. C, The size of basal IK(Ca) was not altered after ethanol treatment. D, Summary graph depicting DHPG effect on IK(Ca) after different periods of ethanol withdrawal [1 d withdrawal group, 14 cells from 8 mice; 7 d withdrawal group, 7 cells from 5 mice; 4–5 week withdrawal group, 10 cells from 5 mice; naive (>8 weeks old) group, 9 cells from 5 mice]. E, DHPG-induced inward currents were not affected by ethanol treatment. Right, Example traces of DHPG-induced currents in cells from saline- and ethanol-treated mice. DHPG was perfused at the time indicated. The data in C and E were obtained from the same cells shown in B.
- Figure 2.
In vivo ethanol exposure increases IP3 sensitivity. A, Traces of IIP3 evoked with different UV pulse intensities (150, 450, 1350, and 4050 μF) in VTA neurons from saline- and ethanol-treated mice. These cells were loaded with caged IP3 (200 μm). UV flashes were applied at the time indicated by the arrow. B, Averaged concentration (UV flash intensity)–response (IIP3) curves from control and ethanol-treated mice. The IIP3 amplitude was normalized to the maximal value (estimated from fit to a logistic equation) in each cell. Data from naive and saline-treated mice were pooled as a control group (control group, 13 cells from 7 naive mice and 6 cells from 4 saline-treated mice; ethanol group, 16 cells from 10 mice; group, F(1,99) = 12.7, p < 0.01; flash intensity, F(3,99) = 643.1, p < 0.0001; group × flash intensity, F(3,99) = 7.45, p < 0.001, mixed two-way ANOVA). Dashed lines are fit to a logistic equation. ***p < 0.001 versus control. C, Summary bar graph showing that EC50 values were reduced in ethanol-treated mice (t33 = 3.88, p < 0.001, unpaired t test). D, The maximal IIP3 amplitude was not altered by in vivo ethanol treatment.
- Figure 3.
Stimulation of the cAMP-PKA pathway increases IP3 sensitivity. A, Representative traces of IIP3 in control (gray) and forskolin (3 μm; black). Traces on the left were elicited with an EC50 flash intensity, while those on the right represent maximal IIP3 evoked in the same cell. The cell was loaded with caged IP3 (200 μm). B, Effects of forskolin on IIP3 evoked with EC50 or maximal flash intensities are plotted in 6 cells (t5 = 9.07, p < 0.001, paired t test). C, Example traces of IK(Ca) in control (gray) and forskolin (10 μm; black). D, Summary time graph demonstrating that forskolin (3–10 μm) failed to affect IK(Ca) (n = 5).
- Figure 4.
CRF amplifies the increase in IP3 effect on AP-evoked Ca2+ signals produced by in vivo ethanol exposure. A, Representative traces of IK(Ca), evoked by itself (gray and orange traces) or paired with preceding photolysis of caged IP3 (25 μm; black and red traces), in a saline-treated mouse. A low-intensity UV flash (100 μF) was applied at the arrow (50 ms before the AP). The magnitude of IP3-induced facilitation of IK(Ca) is determined by comparing gray and black traces in control solution and by comparing orange and red traces in CRF (300 nm). Note that bath perfusion of CRF, which failed to affect IK(Ca) itself, was capable of augmenting IP3-induced facilitation. B, Representative traces of IK(Ca), evoked as in A, from an ethanol-treated mouse. IP3 produced robust facilitation of IK(Ca) (black trace), which was further augmented by CRF (red trace). Treatment with H89 (10 μm) largely suppressed IP3-induced IK(Ca) facilitation and abolished the CRF effect. C, Summary bar graph plotting the magnitude of IP3-induced facilitation of IK(Ca) under the conditions illustrated in A and B (saline group, 8 cells from 4 mice; ethanol group, 6 cells from 4 mice; ethanol group recorded in H89: 6 cells from 5 mice; group: F(2,17) = 11.4, p < 0.001; CRF: F(1,17) = 21.1, p < 0.001; group × CRF: F(2,17) = 4.38, p < 0.05, mixed two-way ANOVA). *p < 0.05, **p < 0.01, ***p < 0.001. D, Summary bar graph depicting the size of IK(Ca) (without IP3). These data were from the same cells shown in C. E, The CRF2 receptor antagonist K41498 blocked the augmentation of IP3-induced facilitation of IK(Ca) by CRF (5 cells from 3 ethanol-treated mice).
- Figure 5.
NMDAR-mediated transmission becomes more susceptible to LTP induction after repeated ethanol exposure. A, Example experiments to induce NMDAR LTP in saline- and ethanol-treated mice. Time graphs of NMDAR EPSC amplitude are shown on the left. The LTP induction protocol, which consisted of synaptic stimulation-burst pairing (top inset), was delivered at the time indicated by the arrow. Traces of NMDAR EPSCs at times indicated by numbers in the time graphs are shown on the right. B, Summary time graph of NMDAR LTP experiments (saline group, 8 cells from 7 mice; ethanol group, 5 cells from 5 mice). C, Summary graph plotting the magnitude of NMDAR LTP in saline- and ethanol-treated mice (t11 = 4.04, p < 0.01, unpaired t test). D, Summary graph showing that the magnitude of IK(Ca) facilitation produced by preceding synaptic stimulation was larger in ethanol-treated mice (t11 = 2.25, p < 0.05, unpaired t test). Example traces illustrating synaptic facilitation of IK(Ca) are shown on the right. E, The magnitude of NMDAR LTP is plotted versus the magnitude of synaptic facilitation of IK(Ca) in the cells shown in. Solid line is a linear fit to all data points from both saline- and ethanol-treated mice. The data summarized in B–E were all from the same cells.
- Figure 6.
Previous ethanol exposure promotes cocaine-induced CPP. A, Changes in the preference for the cocaine-paired side after 2 d conditioning are shown for saline- and ethanol-treated mice (saline group, t6 = 4.46, p < 0.01; ethanol group, t8 = 5.39, p < 0.001, paired t test). B, Summary bar graph showing that cocaine CPP is enhanced in ethanol-treated mice (t14 = 2.35, p < 0.05, unpaired t test). C, Changes in the preference for the ethanol-paired side after 4 d conditioning are shown for saline- and ethanol-treated mice (saline group, t6 = 0.16, p = 0.88; ethanol group, t7 = 1.10, p = 0.31, paired t test). D, Summary bar graph of ethanol CPP experiments (t13 = 0.78, p = 0.45, unpaired t test).
