the presentation of a dipper, or sometimes a sipper tube (Cunningham et al., 2000; Epstein et al., 2006; Leeman et al., 2010; Rodd et al., 2004b; Samson, 2000; Samson and Czachowski, 2003) of ethanol or another palatable fluid (e.g., water, saccharin, etc.). The presentation of the dipper is controlled by a computer program, such that the ratio of lever presses to dipper presentations can be manipulated. Thus, the higher the ratio of lever presses to dipper presentations displayed the greater the amount of work (effort put forth) inferred. Because rats can be trained to press on a lever for access to ethanol, the existing literature using this technique is extensive. This section will provide a brief overview on the use of operant procedures with selectively bred high alcohol-consuming rat lines and general findings on a few compounds targeting alcohol abuse and dependence. Again, a comprehensive summary of ligands, and experimental parameters used in each study, for reducing ethanol intake and/or self-administration by high alcohol-consuming rats is presented in Table 4.
