Dopamine neurotransmission in the VTA regulates appetitive memories persistence

FERNANDO CASTILLO DÍAZ; JORGE H MEDINA; MICAELA ANAHÍ HERNANDEZ; TOMÁS CAPELLÁ

Congreso; FENS FORUM 2018; 2018

Ventral tegmental area (VTA) dopaminergic neurons innervate the hippocampus(HP)and DA neurotransmission has been shown to modulate synaptic plasticity and memory.Dopaminergic inputs to the dorsal HP are involved in the persistence of cocaine-associated memory 12 h after a single dose of cocaine. We aimed to determine which are the brain structures involved in the persistence of this memory from the first exposure to the drug and how they might interact witheach other. We used a conditioned place preference (CPP) paradigm in rats using cocaine as a positive reward. Behavioral experiments were carried out using dopaminergic receptor agonists(SKF 38393) and antagonist s (SCH 23390) infusions into the VTA, nucleus accumbens (NAcc) or medial prefrontal cortex (mPFC). We found that the blockade of the D1/D5 dopamine receptors in the VTA promotes the durability of a weak memory when it is infused immediately or 12 h after conditioning. Biochemical analysis revealed that signaling cascades involved in this process may implicate Erk1/2 pathway. We also found that the neural activity in the VTA or in the NAcc is necessary for the formation of the memory. In contrast, mPFC may not be involved in this type of appetitive memory. Same results as with cocaine were obtained using food as reward showing that the VTA participates in the maintenance of other types of appetitive memories. In conclusion appetitive memories seem to be regulated by the VTA from the beginning of the experience while VTA-HP pathway may regulate its persistence.