Abstract:

The rostromedial tegmental nucleus (RMTg) is located caudally to the ventral tegmental area (VTA), which is rich in inhibitory γ-aminobutyric acid (GABAergic) neurons. The RMTg is an integrative modulator of the mesolimbic dopamine system. Its GABAergic neurons receive input from the lateral habenula (LHb) and then project to VTA dopaminergic neurons, which inhibits the release of dopamine. These three brain areas are an important part of the reward circuit, in which the RMTg plays a particularly important role in reward circuits activated by opioids. GABA neurons in the RMTg are strongly inhibited by opioids, and this is followed by disinhibition of VTA dopaminergic neurons, which activates the reward system. Therefore, the RMTg is a potentially important target for the treatment of drug addiction (especially opioid addiction). Furthermore, cholinergic feedback to the RMTg, acting on muscarinic receptors, can be inhibitory for an opioid-induced reward effect. Future studies should further explore the negative reward circuit regulated by the RMTg, which is of great significance for weakening drug-seeking motivation and promoting extinction and withdrawal.

Key words: reward circuits, rostromedial tegmental nucleus, GABAergic neurons, lateral habenula, opioid addiction