Cl. Czachowski et al., Independent ethanol- and sucrose-maintained responding on a multiple schedule of reinforcement, ALC CLIN EX, 23(3), 1999, pp. 398-403
Assessment of drug effects an two different reinforcers at the same time re
quires that each reinforcer be sampled at approximately the same time. One
procedure that effectively produces this result is the use of a multiple sc
hedule of reinforcement in which two different reinforcers are presented in
alternating P-min components. In our study, sucrose and ethanol solutions
were made available after appropriate lever-press responding, Subjects were
trained to self-administer 10% ethanol using a sucrose-substitution proced
ure and to discriminate light cues associated with the different reinforcer
s until stable reinforcer-directed responding was achieved on both the etha
nol- and the sucrose-associated lever during the changing 2-min components
of the schedule. Subsequently, the reinforcer solution presented on one lev
er was field constant while the concentration of the alternate reinforcer w
as manipulated, i,e,, ethanol concentrations of 0 to 15% end sucrose concen
trations of 0 to 10% were assessed, This multiple schedule procedure result
ed in sustained and independent ethanol- and sucrose-reinforced behavior. M
anipulation of the characteristics of one reinforcer had no effect on behav
ior maintained by the alternate reinforcer, Increases In sucrose concentrat
ion resulted in Increases in sucrose-directed responding with no change in
ethanol responding, and increases in ethanol concentration resulted in incr
eases In ethanol intake with no change in sucrose responding. Our methods c
an be used to examine differential drug effects on ethanol- and sucrose-rei
nforced behavior in the same animal over a single time course without the c
onfounds or interference from the concurrently available reinforcer.