Marion JALABERT Marion JALABERT from Daniel Choquet's IINS lab will present his project entitled 'Neuronal circuits underlying morphine action on dopamine neurons'
Morphine is a highly potent analgesic with high addictive potential in specific contexts. Although dopamine neurons of the ventral tegmental area (VTA) are widely believed to play an essential role in the development of drug addiction, neuronal circuits underlying morphine action on dopamine neurons have not been fully elucidated. Here, we combined in vivo electrophysiology, tract-tracing experiment and targeted neuronal inactivation to dissect the neural circuit for morphine action on dopamine neurons in rats. First, we found that morphine targets in vivo the GABAergic tail of the ventral tegmental area, also called rostromedial tegmental nucleus, disrupting the balance between inhibition and excitation on dopamine neurons. Second, our data reveal that in the absence of VTA glutamatergic tone, there is no morphine-induced activation of dopamine neurons. We conclude that morphine excites dopamine neurons by simultaneous NMDA/AMPA receptor activation and cessation of GABA receptor activation.