Cotreatment with the kappa opioid agonist U69593 enhances locomotor sensitization to the D2/D3 dopamine agonist quinpirole and alters dopamine D2 receptor and prodynorphin mRNA expression in rats. - Perreault,M.L.; Graham,D.; Scattolon,S.; Wang,Y.; Szechtman,H.; Foster,J.A. (Psychopharmacology (Berl), 2007)