Developmental and sensory-dependent changes of group II metabotropic glutamate receptors.
Metabotropic glutamate receptors (mGluRs) are potential participants of sensory-dependent modification of neural connections. Here, we examined the involvement of cAMP-linked mGluRs (mGluR2/3) in sensory-dependent plasticity by studying the correlation of mGluR2/3 changes with the critical period of ocular dominance plasticity, a form of sensory-dependent plasticity, and exploring the effects of dark rearing on mGluR2/3 in the primary visual cortex of cats. Immunohistochemistry showed that the laminar distribution of mGluR2/3 changed with the critical period and was sensitive to dark rearing. The mGluR2/3 immunostaining became most intense in layer IV at the beginning of the critical period and was reduced in layer IV but became intense in layers I-III at the peak of the period, then was concentrated primarily in layers I-upper III at the end of the critical period. Dark rearing delayed these pattern changes for weeks and elevated the normally declining mGluR2/3 quantity shortly after the peak of the critical period. The effects of dark rearing and the correlation of early mGluR2/3 laminar changes with geniculocortical afferent segregation indicate that mGluR2/3 circuitry in the visual cortex is influenced by visual inputs. Our data suggest that mGluR2/3 together with another sensory-influenced mGluR, mGluR5, may participate in the sensory-dependent modification of neural connections in the visual cortex.
Reid
S N
SN
Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, Connecticut 06520-8061, USA. reiddrs@aol.com
Romano
C
C
D000818:Animals; D000831:Animals, Newborn; D015153:Blotting, Western; D002415:Cats; D003624:Darkness; D007150:Immunohistochemistry; D008566:Membranes; D008970:Molecular Weight; D009473:Neuronal Plasticity; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000737:chemistry / Q000378:metabolism*; D014793:Visual Cortex / Q000254:growth & development / Q000378:metabolism*
D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3