Alcohol and Alcoholism Vol. 38, No. 4, pp. 305-309, 2003
© 2003 Medical Council on Alcohol
RELATIONSHIP BETWEEN DOPAMINE D2 RECEPTOR-ASSOCIATED RESPONSES AND OPERANT ETHANOL SELF-ADMINISTRATION IN THE RAT: A FACTOR ANALYSIS
1 Department of Pharmacology, Institute of Psychiatry and Neurology, Sobieskiego 9 St., PL-02957 Warszawa,
2 Medagro International, Warszawa and
3 Department of Experimental and Clinical Pharmacology, Warsaw Medical Academy, Warszawa, Poland
Received 4 November 2002; in revised form 15 January 2003; accepted 10 February 2003
Aims: To characterize the relationship between dopamine D2 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 D2-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 D2 receptors are not primarily involved in the regulation of ethanol reinforcement.