Relationship between dopamine D2 receptor-associated responses and operant ethanol self-administration in the rat: a factor analysis.
OBJECTIVE
To characterize the relationship between dopamine D(2) receptor-associated responses and operant ethanol self-administration in Wistar rats.


METHODS
Thirty-two rats were first tested for apomorphine-induced sniffing and raclopride-induced catalepsy. Subsequently, the same subjects were initiated to lever press for ethanol in the sucrose-fading procedure. The subjects were allowed to respond for 8% v/v ethanol for 20 days. A factor analysis was used to characterize the relationship between D(2)-associated responses and parameters of sucrose and ethanol self-administration.


RESULTS
The analysis revealed three factors accounting for 88.3% of the total variability. The first factor comprised only parameters of ethanol-reinforced behaviour. Parameters of sucrose self-administration and cataleptic responses to raclopride loaded heavily on the second and third factors, respectively. None of the factors comprised apomorphine-induced stereotypy.


CONCLUSIONS
It appears that there is no relationship between apomorphine-induced sniffing, raclopride-induced catalepsy and operant responding for ethanol in Wistar rats. Our results, combined with previous reports, suggest that D(2) receptors are not primarily involved in the regulation of ethanol reinforcement.
Rogowski
Artur
A
Department of Pharmacology, Institute of Psychiatry and Neurology, Sobieskiego 9 St., PL-02957 Warszawa, Poland.
Rokicki
Dariusz
D
Kostowski
Wojciech
W
Bienkowski
Przemyslaw
P
D000818:Animals; D002375:Catalepsy / Q000139:chemically induced; D003216:Conditioning, Operant / Q000187:drug effects* / Q000502:physiology; D065127:Dopamine D2 Receptor Antagonists; D000431:Ethanol / Q000008:administration & dosage*; D005163:Factor Analysis, Statistical; D008297:Male; D020891:Raclopride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D012646:Self Administration / Q000379:methods
D065127:Dopamine D2 Receptor Antagonists; D017448:Receptors, Dopamine D2; D000431:Ethanol; D020891:Raclopride