CB1 receptors regulate alcohol-seeking behavior and alcohol self-administration of alcohol-preferring (P) rats.
BACKGROUND
The endogenous cannabinoid (CB) system mediates a number of behaviors associated with drug-seeking and drug self-administration. In this study the effects of CB1 receptor manipulations on operant ethanol (EtOH) responding during EtOH-seeking, EtOH-relapse as well as on-going EtOH self-administration were determined.


METHODS
Alcohol-preferring (P) rats were trained in 2-lever operant chambers to self-administer 15% EtOH (v/v) and water on a concurrent fixed-ratio 5-fixed-ratio 1 (FR5-FR1) schedule of reinforcement in daily 1-h sessions. After 10 weeks, rats underwent 7 extinction sessions, followed by 2 weeks in their home cages without access to EtOH or operant chambers. Rats were then returned to the operant chambers for testing of EtOH-seeking behavior (no EtOH present) for 4 sessions. After a week in their home cages following the EtOH-seeking test, rats were returned to the operant chambers with access to EtOH and water (relapse). Rats were then maintained in the operant chambers for daily 1-h sessions with access to 15% EtOH and water for several weeks.


RESULTS
The CB1 receptor antagonist (SR141716A), at doses of 1 and 2 mg/kg, i.p. reduced EtOH-seeking and transiently reduced EtOH self-administration during relapse and maintenance. Conversely, treatment with the CB1 receptor agonist CP 55, 940, at doses of 1 and 10 μg/kg i.p., increased EtOH-seeking and EtOH self-administration during relapse.


CONCLUSIONS
The results of this study demonstrate that activation of CB1 receptors are involved in regulating EtOH-seeking as well as the reinforcing effects of EtOH under relapse and on-going self-administration conditions.
Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, USA.
Bruk
B
Getachew
Sheketha R
SR
Hauser
Ronnie
R
Dhaher
Simon N
SN
Katner
Richard L
RL
Bell
Scott M
SM
Oster
William J
WJ
McBride
Zachary A
ZA
Rodd
D000818:Animals; D003216:Conditioning, Operant; D000431:Ethanol / Q000008:administration & dosage*; D005260:Female; D009042:Motivation; D051381:Rats; D043884:Receptor, Cannabinoid, CB1 / Q000502:physiology*; D012646:Self Administration
D043884:Receptor, Cannabinoid, CB1; D000431:Ethanol