Schedule induction and sweetness as factors in ethanol consumption and preference by rats.

The separate and joint effects of spaced feeding of small portions of the daily food ration (schedule induction) and sweetening of one or the other fluid by 0.2% sodium saccharin on the consumption and selection of water and a 5% ethanol solution were examined in three groups of four male, hooded rats. Fluids were available simultaneously throughout 50-min sessions during which 50 Noyes 45-mg pellets were available either altogether at the beginning of each session or singly at 60-sec intervals. Water was available in home cages. Each group experienced a different sequence of procedures that provided alternation and replication of critical conditions. Sweetening increased consumption of the sweetened fluid and suppressed consumption of the unsweetened fluid. Spaced feeding raised consumption of the preferred fluid. Exceptionally high levels of consumption were recorded when one or the other fluid was sweetened and food presentation was intermittent.