Impatto della stimolazione tetanica del ventral subiculum sui neuroni dopaminergici dell’area ventrale tegmentale

The hippocampus (HPC) is recognized as an important structure in learning and memory, including the integration of relevant informations to modulate the behavior. Tetanic burst stimulation of the HPC has been shown to generate adaptive synaptic changes, like long term potentiation (LTP), outside the HPC. Using in vivo extracellular recording techniques in anesthetized rats, we have investigated how the firing of dopaminergic neurons is affected by the delta frequency stimulation of the ventral subiculum of hippocampus (vSUB). This work shows that the delta burst stimulation in vSUB induce a LTP in Bed nucleus of the stria terminalis (BNST) neurons that projecting to the ventral tegmental area (VTA). Also, this LTP is blocked when we administrated the AP5 (a NMDA receptors antagonist) on the BNST neurons before tetanus. In addition, this work shows that 24 hours after the induction of a tetanic stimulation in vSUB, there is an increase of the activity (firing rate, bursting activity) of DA neurons. We also demonstrated that an intra‐BNST infusion of AP5 prior the vSUB tetanus blocks the effect of delta burst stimulation on VTA dopamine neurons bursting parameters. These results contribute to clarify important points concerning the regulation of VTA DA neurons activity by the vSUB, probably through a balance of excitatory and inhibitory inputs from the BNST.