Differential metabotropic glutamate receptor expression and modulation in two neocortical inhibitory networks.
Taking advantage of transgenic mice with genetically labeled GABA-releasing interneurons, we examined the cell-specific patterns of mGluR expression in two broadly defined subtypes of inhibitory interneurons in layer IV of somatosensory cortex. Electrophysiological recording combined with application of specific agonists for specific mGluRs demonstrated different effects of mGluR activation in fast-spiking (FS) versus regular spiking nonpyramidal (RSNP) interneurons. Whereas activation of group I, II, and III mGluRs inhibited excitatory synaptic transmission in RSNP neurons predominantly via postsynaptic mechanisms, group I mGluR activation depolarized FS but not RSNP interneurons. Immunoreactivities of mGluR1, mGluR5, mGluR2/3, and mGluR8 exhibited different cellular expression patterns in the two groups of neurons that were not entirely consistent with physiological and pharmacological experiments. Taken together, our data indicate cell and circuit-specific roles for mGluRs in modulating inhibitory circuits in the somatosensory cortex. These results help to reinforce the concept that RSNP and FS cells represent morphologically, physiologically, and functionally distinct groups of interneurons. The results reported here help to increase our understanding of the roles of mGluRs in endogenous glutamatergic-induced plasticity of interneuronal networks.
Sun
Qian-Quan
QQ
Dept. of Zoology, University of Wyoming, Laramie, WY 82071, USA. neuron@uwyo.edu
Zhang
Zhi
Z
Jiao
Yuanyuan
Y
Zhang
Chunzhao
C
Szabó
Gábor
G
Erdelyi
Ferenc
F
D000200:Action Potentials / Q000187:drug effects / Q000235:genetics; D000704:Analysis of Variance; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002452:Cell Count; D004347:Drug Interactions; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005968:Glutamate Decarboxylase / Q000235:genetics; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics; D007395:Interneurons / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D019579:Neocortex / Q000166:cytology* / Q000378:metabolism*; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism; D010648:Phenylacetates / Q000494:pharmacology; D011422:Propionates / Q000494:pharmacology; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000145:classification / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000235:genetics
C114785:2-amino-4-phosphono-propinate; C107349:2-chloro-5-hydroxyphenylglycine; D000779:Anesthetics, Local; D018690:Excitatory Amino Acid Agonists; D010320:Parvalbumins; D010648:Phenylacetates; D011422:Propionates; D018094:Receptors, Metabotropic Glutamate; D049452:Green Fluorescent Proteins; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1; C401141:glutamate decarboxylase 2; D005998:Glycine