Effects of alcohol consumption induced by reward loss on behavior in the hole-board test.

Rats exposed to reward downshift (from 32 to 4% sucrose) increase 2% alcohol intake in a 2-h, free-choice preference test which also offered water. This effect was accompanied by augmented general activity in the elevated plus maze (Donaire et al., 2018, Behav Proc, 150, 59-65). In the present study we analyzed the effect of alcohol consumption induced by reward downshift on anxiety behaviors registered in the hole-board (HB) test. Sixteen food-deprived female Wistar rats received 32% sucrose for ten 5-min daily sessions and were then downshifted to 4% sucrose for two 5-min daily sessions (postshift). Sessions also involved testing animals in a 2-h, 2-bottle preference task with 2% alcohol vs. water (Group A), or water vs. water (Group W). On postshift sessions, animals were exposed to a 6-min HB test after the preference task. Reward devaluation significantly reduced sucrose intake in Groups A and W, and increased alcohol consumption in Group A, but had no effect on water consumption in Group W. Increased alcohol consumption was followed by higher head-dipping frequency in the HB test compared with Group W. The results are discussed in terms of the impact of reward loss on anxiety behaviors in the HB test and the anxiolytic effects of alcohol in situations involving negative affect.