Pharmacological blockade of corticotropin-releasing hormone receptor 1 (CRH1R) reduces voluntary consumption of high alcohol concentrations in non-dependent Wistar rats.
BACKGROUND
A dysregulation of the corticotropin-releasing hormone (CRH) system has been implicated in the development of excessive alcohol consumption and dependence. The aim of the present study was to evaluate whether the CRH system is also recruited when non-dependent Wistar rats escalate to high alcohol intake in the intermittent (alternate days) model of drinking.


METHODS
We compared intermittent and continuous access to 20% (v/v) alcohol in a two-bottle free choice drinking paradigm. Following a total of twenty 24-hour exposures for every experimental group, we assessed signs of alcohol withdrawal, including anxiety-like behavior and sensitivity to stress. The selective CRH1 receptor (CRH1R) antagonist antalarmin (0, 10, 20 mg/kg, i.p.) was tested on alcohol consumption.


RESULTS
Intermittent access to 20% alcohol led non-selected Wistar rats to escalate their voluntary intake to a high and stable level, whereas continuously exposed animals maintained a lower consumption. These groups did not differ in physical withdrawal signs. In addition, no differences were found when anxiogenic-like behavior was studied, neither under basal conditions or following restraint stress. Nevertheless, sensitivity to the treatment with the CRH1R antalarmin was observed since a reduction of 20% alcohol intake was found in both groups of animals regardless of the regimen of alcohol exposure. In addition, antalarmin was effective when injected to animals exposed to intermittent 10% (v/v) alcohol whereas it failed to suppress 10% continuous alcohol intake.


CONCLUSIONS
Pharmacological blockade of CRH1R reduced alcohol drinking when sustained high levels of intake were achieved suggesting that the CRH system plays a key role when high doses of ethanol are consumed by non-dependent subjects. This supports the notion that CRH system not only maintains the dependent state but also engages the transition to dependence.
Laboratory of Clinical and Translational Studies, National Institute on Alcohol Abuse and Alcoholism (NIAAA), National Institutes of Health (NIH), Bethesda, MD 20892-1108, USA. cippitellia@mail.nih.gov
Andrea
A
Cippitelli
Ruslan
R
Damadzic
Erick
E
Singley
Annika
A
Thorsell
Roberto
R
Ciccocioppo
Robert L
RL
Eskay
Markus
M
Heilig
D000427:Alcohol Deterrents / Q000008:administration & dosage / Q000627:therapeutic use*; D000428:Alcohol Drinking / Q000097:blood / Q000517:prevention & control / Q000523:psychology; D000435:Alcoholic Intoxication / Q000097:blood / Q000517:prevention & control* / Q000523:psychology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects; D000431:Ethanol / Q000097:blood; D008297:Male; D011743:Pyrimidines / Q000008:administration & dosage / Q000627:therapeutic use*; D011758:Pyrroles / Q000008:administration & dosage / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors*; D055502:Secondary Prevention; D013315:Stress, Psychological / Q000503:physiopathology; D013997:Time Factors; D000099052:CRF Receptor, Type 1
D000427:Alcohol Deterrents; D011743:Pyrimidines; D011758:Pyrroles; D018019:Receptors, Corticotropin-Releasing Hormone; C103016:antalarmin; D000431:Ethanol; D000099052:CRF Receptor, Type 1