Chunk #29 — 4. Selectively bred high alcohol-consuming rat lines and their phenotypic characteristics — 4.3. High alcohol-drinking and low alcohol-drinking rats
2006; Rodd et al., 2009; Rodd-Henricks et al., 2000b). When the sedative effects of ethanol were examined, HAD1 rats displayed lower sensitivity, compared with LAD1 rats (Froehlich and Wand, 1997). When testing for the development of tolerance, HAD1 rats displayed rapid tolerance to the ataxic effects of ethanol, whereas LAD1 rats do not (Suwaki et al., 2001). A study of HAD1 vs. LAD1 rats revealed that ethanol-associated withdrawal induces greater dysphoria in LAD1 compared with HAD1 rats (Chester et al., 2006). Both HAD1 and HAD2 rats, but not LAD1 and LAD2 rats, display greater acoustic startle reactivity during ethanol-associated withdrawal compared with basal conditions (Chester et al., 2004). Paradoxically, ethanol-associated withdrawal actually decreased, rather than increased, ethanol drinking in HAD2 rats (Chester et al., 2005). HAD1 and HAD2 rats display greater locomotor activation after low- to moderate-dose ethanol compared with their LAD1 and LAD2 counterparts (Krimmer and Schechter, 1991; Rodd et al., 2004a), suggesting HAD rats find low-dose ethanol rewarding. In summary, the HAD replicate lines meet many of the criteria proposed for an animal model of alcoholism.
