Figure 3.

Receptor-receptor interactions in different types of opioid receptor heteromers in the CNS and their potential role in pharmacotherapy of pain. The homo- and heterodimers would allow direct physical interactions between the receptors making possible the allosteric receptor receptor interactions between them. The functional balance between these oligomers determines the final functional output and thus the eventual cellular response. The schematic representation depicts some of the principal, nonexclusive, molecular mechanisms by which opioid heteromers produce novel functions.