Modulation of brain stimulation reward and locomotor activity by ionotropic glutamate receptors of the tail of the ventral tegmental area.

Modulation of brain stimulation reward and locomotor activity by ionotropic glutamate receptors of the tail of the ventral tegmental area.
Behav Brain Res. 2020 Jun 25;:112785
Authors: Fakhoury M, Hernandez G, Lévesque D, Rompré PP
Abstract
The rostromedial tegmental nucleus also referred to as the tail of the ventral tegmental area (tVTA) contains a cluster of gamma-aminobutyric acid (GABA)ergic neurons that receive dense glutamatergic afferents from the lateral habenula (LHb), and project to dopamine (DA) neurons of the VTA and substantia nigra pars compacta (SNc). In light of previous evidence implicating glutamate transmission in the regulation of midbrain DA neuronal activity, we first assessed the impact of intra-tVTA microinjection of NBQX (0.8 nmol/side) and PPPA (0.825 nmol/side), respectively AMPA and NMDA receptor antagonists, on reward induced by intracranial self-stimulation (ICSS) and on locomotor activity. Since the tVTA contains a large concentration of mu opioid receptors, additional measures were obtained following microinjection of endomorphin-1 (EM-1, 1 nmol/side) to confirm tVTA placements. Then, using small interfering RNAs (siRNAs), we tested the effect of tVTA downregulation of the GluN1 subunit of the NMDA receptor on reward and locomotor activity. Results show that NBQX, PPPA and EM-1 all enhance reward and locomotor activity, effects that were of different magnitude in rostral and intermediate parts...

Source: Behavioural Brain Research - June 24, 2020 Category: Neurology Authors: Fakhoury M, Hernandez G, Lévesque D, Rompré PP Tags: Behav Brain Res Source Type: research