Group I metabotropic @entity2227 receptors (mGluRs) are involved in long-term synaptic plasticity and neuroprotection in the striatum, but the specific role(s) of @entity9446 and @entity10092 remain poorly understood. In this study, we used electron-microscopic immunocytochemistry to compare the pattern of subsynaptic and subcellular distribution of mGluR1a and @entity10092 in relation to putative glutamatergic and dopaminergic inputs to the monkey striatum. At the light-microscopic level, both group I mGluRs are expressed in the striatal neuropil. In addition, numerous perikarya of striatal output neurons are immunostained for @entity10092 , but much less frequently for mGluR1a. At the electron-microscopic level, immunoreactivity for both receptor subtypes is primarily expressed postsynaptically in dendrites and spines, although presynaptic @entity9446 a labeling of glutamatergic thalamostriatal boutons and, less frequently, dopaminergic and corticostriatal terminals is also seen. In contrast to mGluR1a, @entity10092 immunoreactivity is rarely encountered presynaptically. In postsynaptic elements, 40-70% of immunoreactivity for both receptor subtypes is expressed intracellularly, whereas 30-60% is apposed to the plasma membrane. More than 80% of the labeling apposed to the plasma membrane is extrasynaptic. The remaining 20% is located at the edges of putative glutamatergic synapses or in the active zone of symmetric synapses. In @entity10092 -, but not mGluR1a-immunostained sections, approximately 70% of dopaminergic symmetric synapses are labeled perisynaptically. These data emphasize the differential pattern of subsynaptic localization of the two group I mGluRs and provide various presynaptic and postsynaptic sites whereby @entity9446 and @entity10092 could mediate different, but complementary, effects on glutamatergic and dopaminergic transmission in the primate striatum.

Group I metabotropic XXXX receptors in the monkey striatum: subsynaptic association with glutamatergic and dopaminergic afferents.

@entity9446 :: ('14799(Tax:10090)', 'Gene') :: ['mGluR1'] @entity2227 :: ('CHEBI:29987', 'Chemical') :: ['glutamate'] @entity10092 :: ('14805(Tax:10090)', 'Gene') :: ['mGluR5']
@entity2227 :: (CHEBI:29987,Chemical) :: ['glutamate']
