TY - JOUR
T1 - Activation of mGluR2/3 following stress hormone exposure restores sensitivity to alcohol in rats
AU - Jaramillo, Anel A.
AU - Randall, Patrick A.
AU - Frisbee, Suzanne
AU - Fisher, Kristen R.
AU - Besheer, Joyce
N1 - Funding Information:
This work was supported, in part, by funds from the National Institutes of Health AA019682 (JB) and the Bowles Center for Alcohol Studies.
Publisher Copyright:
© 2015 Elsevier Inc.
PY - 2015/9/1
Y1 - 2015/9/1
N2 - Sensitivity to the interoceptive effects of alcohol is blunted following a period of exposure to the stress hormone corticosterone (CORT), an effect that is suggested to be related, in part, to glutamatergic neuroadaptations. Group II metabotropic glutamate receptors (subtypes 2 and 3; mGluR2/3) modulate several drug- and alcohol-related behaviors, including the interoceptive (discriminative stimulus) effects of alcohol. Therefore, we sought to determine if manipulation of mGluR2/3 would restore sensitivity to the interoceptive effects of alcohol following CORT exposure. Using a two-lever drug discrimination task, male Long-Evans rats were trained to discriminate alcohol (1 g/kg, intragastric [IG]) vs. water. First, the effect of mGluR2/3 antagonism on the discriminative stimulus effects of alcohol was determined using LY341495 (0.3-3.0 mg/kg; intraperitoneal [IP]). Next, the effects of mGluR2/3 antagonism and activation were assessed in discrimination-trained animals exposed to CORT (300 μg/mL) in the home cage drinking water or water only, for 7 days. Following CORT exposure, decreased sensitivity to alcohol (1 g/kg) was observed. Pretreatment with the mGluR2/3 agonist LY379268 (1.0-3.0 mg/kg; IP), but not the mGluR2/3 antagonist (0.3-1.0 mg/kg; IP), restored sensitivity to alcohol. Additionally, in water controls, mGluR2/3 antagonism and mGluR2/3 activation disrupted expression of the discriminative stimulus effects of alcohol. Together, these findings suggest that blunted sensitivity to the interoceptive effects of alcohol following an episode of heightened stress hormone levels may be due to adaptations in mGluR2/3-related systems. The ability of mGluR2/3 activation to restore sensitivity to alcohol under these conditions lends further support for the importance of these receptors under stress-related conditions.
AB - Sensitivity to the interoceptive effects of alcohol is blunted following a period of exposure to the stress hormone corticosterone (CORT), an effect that is suggested to be related, in part, to glutamatergic neuroadaptations. Group II metabotropic glutamate receptors (subtypes 2 and 3; mGluR2/3) modulate several drug- and alcohol-related behaviors, including the interoceptive (discriminative stimulus) effects of alcohol. Therefore, we sought to determine if manipulation of mGluR2/3 would restore sensitivity to the interoceptive effects of alcohol following CORT exposure. Using a two-lever drug discrimination task, male Long-Evans rats were trained to discriminate alcohol (1 g/kg, intragastric [IG]) vs. water. First, the effect of mGluR2/3 antagonism on the discriminative stimulus effects of alcohol was determined using LY341495 (0.3-3.0 mg/kg; intraperitoneal [IP]). Next, the effects of mGluR2/3 antagonism and activation were assessed in discrimination-trained animals exposed to CORT (300 μg/mL) in the home cage drinking water or water only, for 7 days. Following CORT exposure, decreased sensitivity to alcohol (1 g/kg) was observed. Pretreatment with the mGluR2/3 agonist LY379268 (1.0-3.0 mg/kg; IP), but not the mGluR2/3 antagonist (0.3-1.0 mg/kg; IP), restored sensitivity to alcohol. Additionally, in water controls, mGluR2/3 antagonism and mGluR2/3 activation disrupted expression of the discriminative stimulus effects of alcohol. Together, these findings suggest that blunted sensitivity to the interoceptive effects of alcohol following an episode of heightened stress hormone levels may be due to adaptations in mGluR2/3-related systems. The ability of mGluR2/3 activation to restore sensitivity to alcohol under these conditions lends further support for the importance of these receptors under stress-related conditions.
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U2 - 10.1016/j.alcohol.2015.03.008
DO - 10.1016/j.alcohol.2015.03.008
M3 - Article
C2 - 26142564
AN - SCOPUS:84940453546
SN - 0741-8329
VL - 49
SP - 525
EP - 532
JO - Alcohol
JF - Alcohol
IS - 6
ER -