Functional characterization of kainate receptors in the rat nucleus accumbens core region

The nucleus accumbens, a brain region involved in motivation, attention, and reward, receives substantial glutamatergic innervation from many limbic structures. This excitatory glutamatergic input plays an integral role in both normal and pathophysiological states. Despite the importance of glutamatergic transmission in the nucleus accumbens, the specific receptor subtypes that mediate glutamatergic signaling in this brain region have not been fully characterized. The current study sought to examine the possible role of the kainate subclass of glutamate receptor in the nucleus accumbens. Kainate receptors are relatively poorly understood members of the ionotropic glutamate receptor family and are highly expressed in the nucleus accumbens. Recent studies have highlighted a number of novel pre- and postsynaptic functions of kainate receptors in several other brain regions. Using the whole cell patch-clamp technique, we report the first demonstration of functional kainate receptors on neurons within the core region of the nucleus accumbens. In addition, we present evidence that activation of kainate receptors in this brain region inhibits excitatory synaptic transmission via a presynaptic mechanism.