Glutamate receptor stimulation induces a persistent rhythmicity of the GABAergic inputs to rat midbrain dopaminergic neurons

The substantia nigra pars compacta and the ventral tegmental area are part of a complex network in the basal ganglia involved in behaviours as diverse as motor planning, generation of pleasure and drug addiction. Here we repo rt that in the dopaminergic neurons of the rat ventral midbrain a brief coa ctivation of group I metabotropic and NMDA glutamate receptors may transfor m a temporally dispersed synaptic GABAergic input into a rhythmic pattern ( range 4.5-22.5 Hz), probably through a mechanism involving electrotonic cou plings. The plastic and long-lasting modification in the temporal code of t he inhibitory synaptic activity induced by glutamate may be a key element i n determining the function of midbrain dopaminergic neurons in both normal and pathological behaviour.