“…Previous studies have reported the role of dopamine in the mechanism of action of antidepressants, focusing on behavioral responses to dopamine agonists after chronic antidepressant treatment or on how selective dopamine receptor antagonists can affect the ability of antidepressants to elicit their behavioral response (Willner and Montgomery, 1981;Maj et al, 1984bMaj et al, , 1989Serra et al, 1990;Gambarana et al, 1995;D'Aquila et al, 2000a). For example, dopamine agonists have shown efficacy in models of behavioral despair and chronic mild stress (Porsolt et al, 1979;Duterte-Boucher et al, 1988;Muscat et al, 1992). Most of the studies have assigned a critical role to D 2 -like receptors, as compared to D 1 -like receptors (Spyraki and Fibiger, 1981;Borsini et al, 1988;Maj et al, 1989Maj et al, , 1996aNunes Junior et al, 1994;Ainsworth et al, 1998b;Rogoz and Dziedzicka-Wasylewska, 1999); however, little is known about the involvement of the individual dopamine receptor subtypes within the D 2 -like family in preclinical models of depression such as the forced swim test (FST).…”