Chunk #26 — 4. Selectively bred high alcohol-consuming rat lines and their phenotypic characteristics — 4.2. Alcohol-preferring and alcohol-nonpreferring rats
least relative to NP rats, P rats display autonomic reactivity to ethanol consumption and its associated cues (Bell et al., 2002, 2008b) similar to that observed in alcohol-dependent and -nondependent individuals with a paternal family history of alcoholism (e.g., Brunelle et al., 2007; Conrod et al., 2001; Peterson et al., 1996; also see Section 4.6.). While not tested thus far, these seeming disparate findings (lower CRF in the hypothalamus of P vs. NP rats and ethanol consumption-induced autonomic reactivity in P rats) may be due to increased sensitivity of the HPA-axis to ethanol in P rats. For instance, alcohol-preferring AA rats display greater ethanol-associated increases in Acb β-endorphin levels compared with their ANA counterparts (Lam et al., 2010). Also, clinically, a positive association between ethanol-induced autonomic (heart rate) reactivity and systemic ethanol-induced β-endorphin levels has been reported by Peterson et al. (1996). In conclusion, the differences observed between the P and NP rats suggest that multiple neurotransmitter and neuro-modulatory systems may contribute to the disparate alcohol drinking behaviors displayed by these two rat lines.
