Increase in alcohol intake, reduced flexibility of alcohol drinking, and evidence of signs of alcohol intoxication in Sardinian alcohol-preferring rats exposed to intermittent access to 20% alcohol.
BACKGROUND
This study assessed in Sardinian alcohol-preferring (sP) rats a procedure known to promote alcohol drinking and based on the intermittent (once every other day) access to 2 bottles containing alcohol (20%, v/v) and water, respectively (Wise, 1973).


METHODS
To this end, sP rats were exposed - under the 2-bottle choice regimen - to: (i) 10% (v/v) alcohol with continuous access (CA10%; i.e., the procedure under which sP rats had been selectively bred); (ii) 10% (v/v) alcohol with intermittent access (IA10%); (iii) 20% (v/v) alcohol with continuous access (CA20%); (iv) 20% (v/v) alcohol with intermittent access (IA20%; the "Wise" condition) (Experiment 1). Additional experiments assessed the influence of (i) adulteration with quinine of the alcohol solution (Experiment 2) and (ii) concurrent presentation of a saccharin solution (Experiment 3) on alcohol drinking under the CA10% and IA20% conditions. Finally, it was assessed whether alcohol drinking under the CA10% and IA20% conditions resulted in motor incoordination at the Rota-Rod task, as a possible sign of alcohol intoxication (Experiment 4).


RESULTS
Daily alcohol intake markedly escalated in rats exposed to the IA20% condition, averaging 9.0 g/kg (in comparison with the average intake of 6.5 g/kg in the CA10% rat group). CA20% and IA10% rats displayed intermediate values of daily alcohol intake between those of CA10% and IA20% rats. Alcohol intake was virtually abolished by addition of quinine or by concurrent presentation of the saccharin solution in CA10% rats; conversely, alcohol intake in IA20% rats was only partially affected by gustatory aversion or concurrent presentation of an alternative reinforcer. Finally, alcohol intake in IA20%, but not in CA10%, rats resulted in clear motor-incoordinating effects.


CONCLUSIONS
These data suggest that the "Wise" procedure is effective in inducing marked increases in alcohol intake in sP rats. These increases are associated with a reduced flexibility of alcohol drinking (suggesting the development of "behavioral" dependence) and produce signs of alcohol intoxication that are not detected when sP rats are exposed to the more conventional CA10% condition.
Loi
Barbara
B
CNR Neuroscience Institute, Viale Diaz, Cagliari, Italy.
Lobina
Carla
C
Maccioni
Paola
P
Fantini
Noemi
N
Carai
Mauro A M
MA
Gessa
Gian Luigi
GL
Colombo
Giancarlo
G
D000428:Alcohol Drinking / Q000503:physiopathology / Q000523:psychology*; D000435:Alcoholic Intoxication / Q000523:psychology*; D000437:Alcoholism / Q000523:psychology; D000818:Animals; D002755:Choice Behavior / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D011803:Quinine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D045442:Rotarod Performance Test; D012439:Saccharin / Q000494:pharmacology
D000431:Ethanol; D011803:Quinine; D012439:Saccharin