(Wisse et al., 2007), whereas we found that at least 1 mg/kg LPS was required for the persistent increase in alcohol consumption. In addition, we saw no correlation between initial weight loss produced by LPS and increased alcohol consumption, suggesting that the later effects of LPS are independent of the acute responses. LPS doses in the range of 0.8–5 mg/kg are commonly used to produce longer-lasting effects of LPS such as depressive-like behavior and neurodegeneration (O’Connor et al., 2009; Qin et al., 2008). Marsh et al. (2009) found that systemic administration of 1 mg/kg LPS repro-grams TLR4-expressing cells within the brain. It appears that the persistent actions of LPS require a higher dose than is needed for the acute effects, although studies with dose–response data are lacking.
