Chunk #35 — 4. Selectively bred high alcohol-consuming rat lines and their phenotypic characteristics — 4.4. Sardinian alcohol-preferring and alcohol-nonpreferring rats
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 densities of opiate receptors in the caudate putamen and Acb shell (Fadda et al., 1999), lower basal levels of μ-opioid receptor mRNA and GTPγS binding in Acb-shell (Zhou et al., in press), and higher basal proopiomelanocortin mRNA levels in hypothalamus (Zhou et al., in press), compared with their sNP counterparts. Higher density of cannabinoid CB1 receptors and levels of CB1 receptor mRNA, CB1 receptor-mediated G-protein coupling, and endocannabinoids have been found in the cerebral cortex, hippocampus and striatum of alcohol-naive sP vs. sNP rats (Vinod et al., 2012). Higher levels of serum corticosterone (Bano et al., 1998) and CRF in the central nucleus of amygdala (Richter et al., 2000) have been reported in sP rats, compared with sNP rats, suggesting differences in the HPA-system as well. Finally, higher basal mRNA levels of the stress-responsive, arginine vasopressin (AVP) gene have been observed in the medial and central amygdala as well as the medial hypothalamus of alcohol-naive sP vs. sNP rats (Zhou
