Chunk #34 — 4. Selectively bred high alcohol-consuming rat lines and their phenotypic characteristics — 4.4. Sardinian alcohol-preferring and alcohol-nonpreferring rats
For neurochemical correlates, whole brain levels of 5-HT and 5-HIAA are higher in sP compared with sNP rats (Bano et al., 1998). However, the sP rat may still display 5-HT deficiencies in discrete brain regions, despite overall increased levels within the brain. Additionally, acute ethanol increases extracellular levels of 5-HT in the frontal cortex of sP, but not sNP, rats (Portas et al., 1994). Compared with the sNP line, the sP line has lower densities of D2 receptors in subregions of the mesolimbic DA system (Stefanini et al., 1992), a finding similar to that reported in P vs. NP rats (McBride et al., 1993a). Basal DA levels are higher in Acb shell and medial prefrontal cortex of sP than sNP rats (Leggio et al., 2003). With regard to GABA, it appears that (a) a mutation in the GABA-A alpha-6 receptor subunit is evident in the sP rat, relative to the sNP rat (Saba et al., 2001) and (b) GABA-B receptor function is lower in limbic areas of sP than sNP rats (Castelli et al., 2005). The sP rat has lower
