“…Furthermore, the D 2 -D 2 homomer findings support observations from various receptor dimers, including the glutamate Hlavackova et al, 2005) and LTB 4 BLT 1 receptors (Damian et al, 2006(Damian et al, , 2008, where maximal receptor signal is achieved only when one protomer is occupied by agonist or, in the case of CXCR2-␦, functionally reconstituted heteromers, where antagonism of CXCR2 by SB225002 enhances the action of ␦ opioid agonists (Parenty et al, 2008). However, such studies indicating asymmetry or single occupancy of homoand heteromers are in contrast to several other reports in which co-occupancy is required.…”