Acetaldehyde oral self-administration: evidence from the operant-conflict paradigm.
BACKGROUND
Acetaldehyde (ACD), ethanol's first metabolite, has been reported to interact with the dopaminergic reward system, and with the neural circuits involved in stress response. Rats self-administer ACD directly into cerebral ventricles, and multiple intracerebroventricular infusions of ACD produce conditioned place preference. Self-administration has been largely employed to assess the reinforcing and addictive properties of most drugs of abuse. In particular, operant conditioning is a valid model to investigate drug-seeking and drug-taking behavior in rats.


METHODS
This study was aimed at the evaluation of (i) the motivational properties of oral ACD in the induction and maintenance of an operant-drinking behavior; (ii) ACD effect in a conflict situation employing the punishment-based Geller-Seifter procedure; and (iii) the onset of a relapse drinking behavior, following ACD deprivation. The lever-pressing procedure in a sound-attenuated operant-conditioning chamber was scheduled into 3 different periods: (i) training-rewarded responses with a fixed ratio 1; (ii) conflict-rewarded responses periodically associated with a 0.2 mA foot-shock; and (iii) relapse-rewarded lever presses following 1-week ACD abstinence.


RESULTS
Our results show that oral self-administrated ACD induced: a higher rate of punished responses in Geller-Seifter procedures; and the establishment of a relapse behavior following ACD deprivation.


CONCLUSIONS
In conclusion, our results indicate that ACD is able to induce an operant-drinking behavior, which is also maintained besides the conflict procedure and enhanced by the deprivation effect, supporting the hypothesis that ACD itself possesses motivational properties, such as alcohol and other substances of abuse.
Department of Science for Health Promotion G. D'Alessandro, Section of Pharmacology, University of Palermo, Palermo, Italy.
Silvana
S
Cacace
Fulvio
F
Plescia
Ignazio
I
Barberi
Carla
C
Cannizzaro
D000079:Acetaldehyde / Q000008:administration & dosage*; D000284:Administration, Oral; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects* / Q000502:physiology; D003220:Conflict, Psychological; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012646:Self Administration
D000079:Acetaldehyde