Development of MK-801, kainate, AMPA, and muscimol binding sites and the effect of dark rearing in rat visual cortex

Abstract

We used quantitative autoradiography to determine whether the development of glutamate receptors correlates with the plastic period for monocular deprivation in rat visual cortex. To study glutamate receptors, we incubated sections of rat visual cortex with tritiated (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10imin e maleate (MK-801), tritiated kainate, and tritiated amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA). [3H]MK-801 is a noncompetitive ligand for the N-methyl-D-aspartate (NMDA) receptor. [3H]kainate and [3H]AMPA are competitive ligands for non-NMDA receptors. To compare glutamate binding sites with a nonglutamate binding site, we studied [3H]muscimol, which binds to gamma-aminobutyric acid (GABA)A receptors. [3H]MK-801 binding was maximal at postnatal day 26 (P26) and decreased in adulthood. [3H]AMPA binding was maximal at P18. [3H]kainate binding and [3H]muscimol binding were not age dependent. Dark rearing partially prevented the age-dependent decrease in [3H]MK-801 binding but had no effect on [3H]kainate or [3H]AMPA binding. Dark rearing decreased muscimol binding in adult animals. These results suggest that NMDA receptors, but not other glutamate receptors or GABAA receptors, are likely to be critical for developmental plasticity in rat visual cortex.

Dark rearing reveals the mechanism underlying stimulus size tuning of superior colliculus neurons

“…746 Khaleel A. Razak and Sarah L. Pallas size tuning and inhibition were indirectly caused by altered NMDA-R function however, given our result that chronic blockade of NMDA-R does not alter either property~size tuning- Razak et al, 2003; inhibition-this study!. One possible reason for the difference in the effects of DR and NMDA-R blockade on size tuning and inhibition within the RF may be that these properties depend on AMPA-R function, which is unaltered by DR in rodent SC and cat cortex~Binns & Salt, 1998;Gordon et al, 1997!. Our finding that DR reduces inhibition within the RF suggests that light-driven neural activity is necessary for developing the normal balance between inhibitory and excitatory input strength. It cannot be determined conclusively from our data whether the maturation of this balance or its maintenance in adults was affected by dark rearing.…”

Postnatal Development of NR2A and NR2B mRNA Expression in Rat Auditory Cortex and Thalamus

“…In ACx, all layers except layer 1 show expression, with the highest levels in layers 2/3. This ®nding is generally consistent with studies of adult and developing cortex that show high levels of NMDAR mRNA and protein in super®cial layers (Monaghan and Cotman 1985;Watanabe et al 1993;Gordon et al 1997), but note that studies directed at visual cortex have obtained somewhat different quantitative laminar pro®les (Nase et al 1999;Cao et al 2000b). Layers 2/3 of primary ACx receives inputs from and project to other cortical regions (Wallace et al 1991;Winer 1992), whereas layers 3/4 receive thalamic input from the primary auditory relay in MGv (Mitani and Shimokouchi 1985;Winer 1992;Romanski and LeDoux 1993).…”

Laminar distribution and co-distribution of neurotransmitter receptors in early human visual cortex

“…The laminar preferences of AMPA (layers II, V/VI), NMDA (layers II, III and IVc in primary, II, III in higher visual areas) and kainate (layers IV/VI and I/II) receptors observed in the present study matches previous data from humans (Albin et al 1991;Carlson et al 1993) and macaque monkeys (Huntley et al 1994;Rosier et al 1993). For primary visual cortex, the laminar distributions of glutamatergic receptors in humans is also in good correspondence to those described for cats (e.g., Rosier et al 1995), rats (e.g., Gordon et al 1997) and ferrets (Smith and Thompson 1994). For higher visual areas this comparison becomes difficult due to the uncertain homologies of the extrastriate cortex in these species.…”

“…GABAergic receptors GABA A and BZ receptors, which provide the major mechanisms for intra-cortical inhibition, were found in high concentrations mainly in layers II, III and IVc of striate cortex, which is in good agreement to previous reports in man (Albin et al 1991;Hendry et al 1994), marmoset monkeys (Gebhard et al 1993), macaques (Hendry and Carder 1992;Hendry et al 1990;Rakic et al 1988) and rats (Gordon et al 1997;Kumar and Schliebs 1993). Peaks of the cortical GABA A receptor concentration in layers V and VI as reported in macaque monkeys (Hendry et al 1990;Rakic et al 1988), however, could not be observed.…”

“…Similarities in laminar distribution patterns between different receptors have also been observed as, e.g., many receptors are found with higher concentrations in suprathan in infragranular layers (Zilles et al 2002a(Zilles et al , 2003(Zilles et al , 2004. Furthermore, laminar receptor distribution patterns have not only been described in the human cerebral cortex, but also in the cortices of other mammalian species such as marmosets (Gebhard et al 1993) and macaques (Hendry and Carder 1992;Hendry et al 1990), cats (Gordon et al 1996;Rosier et al 1995), rats (Gordon et al 1997;Kumar and Schliebs 1993) and ferrets (Smith and Thompson 1994). These observations raise three important questions, which were addressed in the present study by statistical analysis of the laminar distribution patterns of 16 neurotransmitter receptors in human visual areas V1-V3.…”