that Intralipid, which increases circulating TG and OX expression in the PFLH, has a stimulatory effect on ethanol drinking in rats (Carrillo et al., 2004; Chang et al., 2004). Direct evidence for a positive relationship between OX and ethanol is provided by injection studies, which show a stimulation of ethanol intake after hypothalamic injection of OX and a reduction in ethanol consumption after peripheral injections of an OX receptor antagonist (Lawrence et al., 2006; Schneider et al., 2007). There is evidence that OX neurons of the PFLH regulate both reward processing for food and drugs of abuse as well as arousal and responses to stress (Harris and Aston-Jones, 2006). The present study demonstrates the importance of OX in the control of ethanol intake and its close association with circulating TG. Further studies with opioid peptides, which are known to respond to TG (Chang et al., 2007b), may reveal a similar relationship in the control of ethanol intake. The evidence presented here with OX is the first to suggest that lipid lowering drugs such as gemfibrozil may be of use in the treatment of alcohol abuse.
