Chronic Intermittent Ethanol Exposure Alters Stress Effects on (3α,5α)-3-hydroxy-pregnan-20-one (3α,5α-THP) Immunolabeling of Amygdala Neurons in C57BL/6J Mice - PubMed (original) (raw)
Chronic Intermittent Ethanol Exposure Alters Stress Effects on (3α,5α)-3-hydroxy-pregnan-20-one (3α,5α-THP) Immunolabeling of Amygdala Neurons in C57BL/6J Mice
Antoniette M Maldonado-Devincci et al. Front Cell Neurosci. 2016.
Abstract
The GABAergic neuroactive steroid (3α,5α)-3-hydroxy-pregnan-20-one (3α,5α-THP, allopregnanolone) is decreased in various brain regions of C57BL/6J mice following exposure to an acute stressor or chronic intermittent ethanol (CIE) exposure and withdrawal. It is well established that there are complex interactions between stress and ethanol drinking, with mixed literature regarding the effects of stress on ethanol intake. However, there is little research examining how chronic ethanol exposure alters stress responses. The present work examined the impact of CIE exposure and withdrawal on changes in brain levels of 3α,5α-THP, as well as hormonal and behavioral responses to forced swim stress (FSS). Adult male C57BL/6J mice were exposed to four cycles of CIE to induce ethanol dependence. Following 8 h or 72 h withdrawal, mice were subjected to FSS for 10 min, and 50 min later brains were collected for immunohistochemical analysis of cellular 3α,5α-THP. Behavioral and circulating corticosterone responses to FSS were quantified. Following 8 h withdrawal, ethanol exposure potentiated the corticosterone response to FSS. Following 72 h withdrawal, this difference was no longer observed. Following 8 h withdrawal, stress-exposed mice showed no differences in immobility, swimming or struggling behavior. However, following 72 h withdrawal, ethanol-exposed mice showed less immobility and greater swimming behavior compared to air-exposed mice. Interestingly, cellular 3α,5α-THP levels were increased in the lateral amygdala 8 h and 72 h post-withdrawal in stressed ethanol-exposed mice compared to ethanol-exposed/non-stressed mice. In the paraventricular nucleus of the hypothalamus, stress exposure decreased 3α,5α-THP levels compared to controls following 72 h withdrawal, but no differences were observed 8 h post-withdrawal. There were no differences in cellular 3α,5α-THP levels in the nucleus accumbens shell at either withdrawal time point. These data suggest that there are different mechanisms mediating hormonal, behavioral, and brain responses to stress following CIE exposure. The lateral amygdala appears to be an extremely sensitive brain region exhibiting changes in cellular 3α,5α-THP levels following CIE and exposure to swim stress. It is likely that these changes in cellular 3α,5α-THP levels in the lateral amygdala contribute to the behavioral effects observed following 72 h withdrawal.
Keywords: 3α; 5α-THP; alcohol; allopregnanolone; mouse; neuroactive steroid; stress; withdrawal.
Figures
Figure 1
Effects of chronic intermittent ethanol (CIE) or air exposure on circulating corticosterone (ng/ml) levels following (A) 8 h or (B) 72 h post-withdrawal in non-stressed (clear bars) or stressed mice (gray bars). Data are depicted as mean difference between post-stress and baseline corticosterone levels ±SEM. #Indicates main effect of Stress (p < 0.0001).
Figure 2
Behavioral response to forced swim stress (FSS) following (A) 8 h or (B) 72 h withdrawal in air-exposed (clear bars) or ethanol-exposed mice (gray bars). Data are depicted as mean time engaged in each behavior ±SEM. *p < 0.05 compared to respective Air-Stress group. **p < 0.005 compared to respective Air-Stress group.
Figure 3
Effects of CIE or air exposure on 3α,5α-THP immunoreactivity in the lateral amygdala following (A) 8 h or (B) 72 h post-withdrawal in non-stressed (clear bars) or stressed mice (gray bars). Data depicted are mean positive pixels/mm2 expressed as percent control ±SEM. (C) Red box indicates coordinates relative to bregma depicted in photomicrographs. Representative photomicrographs (10x) of 3α,5α-THP immunoreactivity 72 h post-withdrawal following CIE and/or stress exposure. *p < 0.05 compared to Ethanol-No Stress group; ∧p < 0.05 compared to Ethanol-No Stress and Air-Stress group.
Figure 4
Effects of CIE or air exposure on 3α,5α-THP immunoreactivity in the paraventricular nucleus of the hypothalamus following (A) 8 h or (B) 72 h post-withdrawal in non-stressed (clear bars) or stressed mice (gray bars). Data depicted are mean positive pixels/mm2 expressed as percent control ±SEM. (C) Red box indicates coordinates relative to bregma depicted in photomicrographs. Representative photomicrographs (10x) of 3α,5α-THP immunoreactivity 72 h post-withdrawal following CIE and/or stress exposure. *p < 0.05 compared to Air-No Stress group.
Figure 5
Effects of CIE or air exposure on 3α,5α-THP immunoreactivity in the nucleus accumbens shell following (A) 8 h or (B) 72 h post-withdrawal in non-stressed (clear bars) or stressed mice (gray bars). Data depicted are mean positive pixels/mm2 expressed as percent control ±SEM. (C) Red box indicates coordinates relative to bregma depicted in photomicrographs. Representative photomicrographs (10x) of 3α,5α-THP immunoreactivity 72 h post-withdrawal following CIE and/or stress exposure.
References
- Adinoff B., Martin P. R., Bone G. H., Eckardt M. J., Roehrich L., George D. T., et al. (1990). Hypothalamic–pituitary–adrenal axis functioning and cerebrospinal fluid corticotropin releasing hormone and corticotropin levels in alcoholics after recent and long-term abstinence. Arch. Gen. Psychiatry 47, 325–330. 10.1001/archpsyc.1990.01810160025004 - DOI - PubMed
- Beckley E. H., Fretwell A. M., Tanchuck M. A., Gililland K. R., Crabbe J. C., Finn D. A. (2008). Decreased anticonvulsant efficacy of allopregnanolone during ethanol withdrawal in female Withdrawal Seizure-Prone vs. Withdrawal Seizure-Resistant mice. Neuropharmacology 54, 365–374. 10.1016/j.neuropharm.2007.10.006 - DOI - PMC - PubMed
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