Initiation of ethanol self-administration in the rat using sucrose substitution in a sipper-tube procedure.
BACKGROUND
The concepts of appetitive and consummatory behaviors provide a framework for examining ethanol-drinking behavior. However, traditional studies of ethanol self-administration using dipper procedures make separating the appetitive from the consummatory components difficult.


OBJECTIVE
This study compared the ability to initiate ethanol self-administration using a new sipper-tube self-administration procedure with the older established sucrose-substitution initiation model that employed dipper presented reinforcement. The new model was developed to allow for an assessment of the appetitive and consummatory components in ethanol self-administration.


METHODS
For the sipper-tube procedure, the rats were initiated to self-administer ethanol using a sucrose-substitution procedure that provided limited access to a sipper tube containing ethanol. This procedure required the completion of a fixed ratio requirement (FR4) in order to gain access to a sipper tube for 20 min. Initially, a 20% sucrose solution with no ethanol was provided in the sipper tube. Over sessions, the concentration of sucrose was reduced and the ethanol concentration increased, until 10% ethanol in water was the solution presented. A second group of animals was initiated to self-administer ethanol using the dipper-presentation procedure employed in our laboratory for many years. This group was used for comparison of the effectiveness of initiation in the sipper-tube procedure.


RESULTS
Following initiation, the sipper-tube rats self-administered 10% ethanol in water with intakes averaging 0.75 g/kg during the 20-min drinking period. Increasing the ethanol concentrations as high as 20%, increased intakes as high as 1.5 g/kg. The ethanol intakes observed were similar to those obtained with the dipper initiation procedure but occurred in one-third of the time.


CONCLUSIONS
The sipper-tube procedure employed here results in similar ethanol self-administration behavior as has been found with a dipper presentation procedure. More importantly, however, it allows for a separation of the appetitive and consummatory components of ethanol self-administration. This separation may prove useful for examining the strength of ethanol-seeking behaviors without the confound of increasing levels of ethanol interacting with the appetitive seeking behaviors.
Samson
H H
HH
Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083, USA. hsamson@wfubmc.edu
Sharpe
A L
AL
Denning
C
C
D000428:Alcohol Drinking / Q000523:psychology*; D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D012055:Reinforcement Schedule; D012646:Self Administration; D013395:Sucrose / Q000494:pharmacology*
D013395:Sucrose