Shift from depolarizing to hyperpolarizing glycine action occurs at different perinatal ages in superior olivary complex nuclei

Löhrke, Stefan; Srinivasan, Geetha; Oberhofer, Martin; Doncheva, Ekaterina; Friauf, Eckhard

doi:10.1111/j.1460-9568.2005.04465.x

Cited by 67 publications

(87 citation statements)

References 47 publications

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“…8A). This localization was also consistent with previous reports on KCC2 expression in other brain areas (Lohrke et al, 2005;Vale et al, 2005). No specific staining was evident in the angular bundle, which served as reference to evaluate nonspecific signal.…”

Section: Densitometric Analysis Of Kcc2 Immunohistochemistrysupporting

confidence: 80%

“…We used a commercially available specific antibody (Vale et al, 2003;Grob and Mouginot, 2005;Lohrke et al, 2005) to evaluate KCC2 expression in the PC. The distribution of KCC2 immunoreactivity in NEC tissue was as previously described in other cerebral regions such as the subiculum (de Guzman et al, 2006): immunostaining was localized in neuronal processes and on the surface of neuronal cell bodies, whereas the cytoplasm appeared completely devoid of any signal (arrows in Fig.…”

Section: Densitometric Analysis Of Kcc2 Immunohistochemistrymentioning

confidence: 99%

“…Changes in KCC2 immuno-reactivity were assessed with a polyclonal antibody (product code no. 07-432, Upstate, NY), which was shown to be specific (Vale et al, 2003(Vale et al, , 2005Grob and Mouginot, 2005;Lohrke et al, 2005;de Guzman et al, 2006), used at 1:1,000 dilution on 50-μm-thick horizontal sections obtained, respectively, at levels −6.82 and −7.60 from Bregma (Paxinos and Watson, 2007). In close sections, we examined the presence of neuronal cell loss by using a monoclonal antibody against the specific neuronal cell nuclear antigen NeuN (1:100; no.…”

Section: Introductionmentioning

confidence: 99%

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Perirhinal cortex hyperexcitability in pilocarpine‐treated epileptic rats

et al. 2011

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The perirhinal cortex (PC), which is heavily connected with several epileptogenic regions of the limbic system such as the entorhinal cortex and amygdala, is involved in the generation and spread of seizures. However, the functional alterations occurring within an epileptic PC network are unknown. Here, we analyzed this issue by using in vitro electrophysiology and immunohistochemistry in brain tissue obtained from pilocarpine-treated epileptic rats and agematched, nonepileptic controls (NECs). Neurons recorded intracellularly from the PC deep layers in the two experimental groups had similar intrinsic and firing properties and generated spontaneous depolarizing and hyperpolarizing postsynaptic potentials with comparable duration and amplitude. However, spontaneous and stimulus-induced epileptiform discharges were seen with field potential recordings in over one-fifth of pilocarpine-treated slices but never in NEC tissue. These network events were reduced in duration by antagonizing NMDA receptors and abolished by NMDA + non-NMDA glutamatergic receptor antagonists. Pharmacologically isolated isolated inhibitory postsynaptic potentials had reversal potentials for the early GABA A receptor-mediated component that were significantly more depolarized in pilocarpine-treated cells. Experiments with a potassium-chloride cotransporter 2 antibody identified, in pilocarpine-treated PC, a significant immunostaining decrease that could not be explained by neuronal loss. However, interneurons expressing parvalbumin and neuropeptide Y were found to be decreased throughout the PC, whereas cholecystokinin-positive cells were diminished in superficial layers. These findings demonstrate synaptic hyper-excitability that is contributed by attenuated inhibition in the PC of pilocarpine-treated epileptic rats and underscore the role of PC networks in temporal lobe epilepsy.

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Section: Densitometric Analysis Of Kcc2 Immunohistochemistrysupporting

confidence: 80%

Section: Densitometric Analysis Of Kcc2 Immunohistochemistrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Perirhinal cortex hyperexcitability in pilocarpine‐treated epileptic rats

et al. 2011

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“…The oligomeric KCC2-immunoreactive signals observed at P1/P2 (13%) are likely attributable to some brainstem regions already containing transport-active KCC2 and displaying effective Cl Ϫ extrusion, such as the superior paraolivary nucleus (Löhrke et al, 2005) or the respiratory center (Ikeda et al, 2004). Because functional CCCs are most likely oligomers, the lack of effective KCC2 transport activity in immature neurons can be explained by the prevailing monomeric form at this stage (Fig.…”

Section: Oligomerization Of Kcc2 Correlates With Onset Of CLmentioning

confidence: 99%

“…10). This time window was chosen because [Cl Ϫ ] i is still high in most brain areas at P4 yet has become low by P12 [neocortex (Owens et al, 1996), hippocampus (Ben Ari et al, 1989;Rivera et al, 1999), hypothalamus (Wang et al, 2001), ventral tegmental area (Ye, 2000), cerebellum (Eilers et al, 2001), SOC (Ehrlich et al, 1999;Kakazu et al, 1999;Löhrke et al, 2005)]. At P4, moderate to strong KCC2-IR was restricted to some brain regions, namely the glomeruli and mitral cell layer of the olfactory bulb, the rostrodorsal region of the caudate-putamen, the thalamus, the hypothalamus, the superior colliculus, the inferior colliculus, the pons, and the medulla oblongata, including the SOC (Fig.…”

Section: Kcc2-ir Throughout the Developing Brainmentioning

confidence: 99%

Oligomerization of KCC2 Correlates with Development of Inhibitory Neurotransmission

Blaesse¹,

Guillemin²,

Schindler³

et al. 2006

J. Neurosci.

225

244

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The neuron-specific K ϩ -Cl Ϫ cotransporter KCC2 extrudes Cl Ϫ and renders GABA and glycine action hyperpolarizing. Thus, it plays a pivotal role in neuronal inhibition. Development-dependent KCC2 activation is regulated at the transcriptional level and by unknown posttranslational mechanisms. Here, we analyzed KCC2 activation at the protein level in the developing rat lateral superior olive (LSO), a prominent auditory brainstem structure. Electrophysiology demonstrated ineffective KCC2-mediated Cl Ϫ extrusion in LSO neurons at postnatal day 3 (P3). Immunohistochemical analyses by confocal and electron microscopy revealed KCC2 signals at the plasma membrane in the somata and dendrites of both immature and mature neurons. Biochemical analysis demonstrated mature glycosylation pattern of KCC2 at both stages. Immunoblot analysis of the immature brainstem demonstrated mainly monomeric KCC2. In contrast, three KCC2 oligomers with molecular masses of ϳ270, ϳ400, and ϳ500 kDa were identified in the mature brainstem. These oligomers were sensitive to sulfhydryl-reducing agents and resistant to SDS, contrary to the situation seen in the related Na ϩ -(K ϩ )-Cl Ϫ cotransporter. In HEK-293 cells, coexpressed hemagglutinin-tagged KCC2 assembled with histidine-tagged KCC2, demonstrating formation of homomers. Based on these findings, we conclude that the oligomers represent KCC2 dimers, trimers, and tetramers. Finally, immunoblot analysis identified a development-dependent increase in the oligomer/monomer ratio from embryonic day 18 to P30 throughout the brain that correlates with KCC2 activation. Together, our data indicate that the developmental shift from depolarization to hyperpolarization can be determined by both increased gene expression and KCC2 oligomerization.

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Regulation of KCC2 and NKCC during development: Membrane insertion and differences between cell types

2006

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The developmental switch of GABA's action from excitation to inhibition is likely due to a change in intracellular chloride concentration from high to low. Here we determined if the GABA switch correlates with the developmental expression patterns of KCC2, the chloride extruder K+-Cl- cotransporter, and NKCC, the chloride accumulator Na+-K+-Cl- cotransporter. Immunoblots of ferret retina showed that KCC2 upregulated in an exponential manner similar to synaptophysin (a synaptic marker). In contrast, NKCC, which was initially expressed at a constant level, upregulated quickly between P14 and P28, and finally downregulated to an adult level that was greater than the initial phase. At the cellular level, immunocytochemistry showed that in the inner plexiform layer KCC2's density increased gradually and its localization within ganglion cells shifted from being primarily in the cytosol (between P1-13) to being in the plasma membrane (after P21). In the outer plexiform layer, KCC2 was detected as soon as this layer started to form and increased gradually. Interestingly, however, KCC2 was initially restricted to photoreceptor terminals, while in the adult it was restricted to bipolar dendrites. Thus, the overall KCC2 expression level in ferret retina increases with age, but the time course differs between cell types. In ganglion cells the upregulation of KCC2 by itself cannot explain the relatively fast switch in GABA's action; additional events, possibly KCC2's integration into the plasma membrane and downregulation of NKCC, might also contribute. In photoreceptors the transient expression of KCC2 suggests a role for this transporter in development.

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Shift from depolarizing to hyperpolarizing glycine action occurs at different perinatal ages in superior olivary complex nuclei

Cited by 67 publications

References 47 publications

Perirhinal cortex hyperexcitability in pilocarpine‐treated epileptic rats

Perirhinal cortex hyperexcitability in pilocarpine‐treated epileptic rats

Oligomerization of KCC2 Correlates with Development of Inhibitory Neurotransmission

Regulation of KCC2 and NKCC during development: Membrane insertion and differences between cell types

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