title: Spatially distinct actions of metabotropic glutamate receptor activation in dorsal lateral geniculate nucleus.
abstract: Thalamocortical neurons in the dorsal lateral geniculate nucleus (dLGN) dynamically communicate visual information from the retina to the neocortex, and this process can be modulated via activation of metabotropic glutamate receptors (mGluRs). Neurons within dLGN express different mGluR subtypes associated with distinct afferent synaptic pathways; however, the physiological function of this organization is unclear. We report that the activation of mGluR(5), which are located on presynaptic dendrites of local interneurons, increases GABA output that in turn produces an increased inhibitory activity on proximal but not distal dendrites of dLGN thalamocortical neurons. In contrast, mGluR(1) activation produces strong membrane depolarization in thalamocortical neurons regardless of distal or proximal dendritic locations. These findings provide physiological evidence that mGluR(1) appear to be distributed along the thalamocortical neuron dendrites, whereas mGluR(5)-dependent action occurs on the proximal dendrites/soma of thalamocortical neurons. The differential distribution and activation of mGluR subtypes on interneurons and thalamocortical neurons may serve to shape excitatory synaptic integration and thereby regulate information gating through the thalamus.
authors.affiliation: Department of Molecular and Integrative Physiology, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: Gubbi
authors.initials: G
authors.lastname: Govindaiah
authors.forename: Deepa V
authors.initials: DV
authors.lastname: Venkitaramani
authors.forename: Sulalita
authors.initials: S
authors.lastname: Chaki
authors.forename: Charles L
authors.initials: CL
authors.lastname: Cox
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001703:Biophysics; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D005829:Geniculate Bodies / Q000166:cytology* / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011724:Pyridazines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D018690:Excitatory Amino Acid Agonists; D018756:GABA Antagonists; D011724:Pyridazines; D018094:Receptors, Metabotropic Glutamate; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D008734:Methoxyhydroxyphenylglycol; C049853:gabazine; D005968:Glutamate Decarboxylase; C401141:glutamate decarboxylase 2; C010117:3,4-dihydroxyphenylglycol