In a relatively recent study looking at the expression of PPAR-γ protein in circulating monocytes and macrophages from healthy smokers and non-smokers, it was found that PPAR-γ protein expression is increased in smokers as compared to non-smokers (72). To confirm these findings, cells from healthy non-smokers were treated in vitro with nicotine and PPAR-γ protein quantified; a dose-dependent increase in expression was found after nicotine treatment. These effects were reversed by bungarotoxin. Although indicative of a link between nicotine effects and PPAR-γ protein, clear evidence for a role of this receptor in addiction came from studies on alcohol carried out in our laboratory (73).
