Selective Assembly of TRPC Channels in the Rat Retina during Photoreceptor Degeneration.

Transient receptor potential canonical (TRPC) channels are calcium channels with diverse expression profiles and physiological implications in the retina. Neurons and glial cells of rat retinas with photoreceptor degeneration caused by retinitis pigmentosa (RP) exhibit basal calcium levels that are above those detected in healthy retinas. Inner retinal cells are the last to degenerate and are responsible for maintaining the activity of the visual cortex, even after complete loss of photoreceptors.

Robust expression of the TRPC1 channel associated with photoreceptor loss in the rat retina.

Baseline intracellular calcium levels are significantly higher in neuronal and glial cells of rat retinas with retinitis pigmentosa (RP). Although this situation could initiate multiple detrimental pathways that lead to cell death, we considered the possibility of TRPC1 being involved in maintaining calcium homeostasis in the retina by acting as a component of store-operated calcium (SOC) channels with special relevance during photoreceptor degeneration. In this study, we examined by Western blot the expression of TRPC1 in healthy control rat retinas (Sprague-Dawley, SD) and retinas with RP (P23H-1 rats).

Pre- and postsynaptic alterations in the visual cortex of the P23H-1 retinal degeneration rat model.

P23H rats express a variant of rhodopsin with a mutation that leads to loss of visual function with similar properties as human autosomal dominant retinitis pigmentosa (RP). The advances made in different therapeutic strategies to recover visual system functionality reveal the need to know whether progressive retina degeneration affects the visual cortex structure. Here we are interested in detecting cortical alterations in young rats with moderate retinal degeneration, and in adulthood when degeneration is severer.

TRPC1 Channels Are Expressed in Pyramidal Neurons and in a Subset of Somatostatin Interneurons in the Rat Neocortex.

Disturbances in calcium homeostasis due to canonical transient receptor potential (TRPC) and/or store-operated calcium (SOC) channels can play a key role in a large number of brain disorders. TRPC channels are plasma membrane cation channels included in the transient receptor potential (TRP) superfamily. The most widely distributed member of the TRPC subfamily in the brain is TRPC1, which is frequently linked to group I metabotropic glutamate receptors (mGluRs) and to the components of SOC channels.

Absence of Notch1 in murine myeloid cells attenuates the development of experimental autoimmune encephalomyelitis by affecting Th1 and Th17 priming.

Inhibition of Notch signalling in T cells attenuates the development of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Growing evidence indicates that myeloid cells are also key players in autoimmune processes. Thus, the present study evaluates the role of the Notch1 receptor in myeloid cells on the progression of myelin oligodendrocyte glycoprotein (MOG) -induced EAE, using mice with a myeloid-specific deletion of the Notch1 gene (MyeNotch1KO).

TRPC1 and metabotropic glutamate receptor expression in rat auditory midbrain neurons.

Canonical transient receptor potential (TRPC) channels are plasma membrane cation channels included in the TRP superfamily. TRPC1 is expressed widely in the central nervous system and is linked to group I metabotropic glutamate receptors (mGluRs). In the auditory brainstem, TRPC1 expression has never been described, although group I mGluRs are present.

Relationship between rat retinal degeneration and potassium channel KCNQ5 expression.

KCNQ5/Kv7.5 is a low-threshold non-inactivating voltage-gated potassium channel preferentially targeted to excitatory endings in brain neurons. The M-type current is mediated by KCNQ5 channel subunits in monkey retinal pigment epithelium cells and in brain neurons.

Loss of auditory activity modifies the location of potassium channel KCNQ5 in auditory brainstem neurons.

KCNQ5/Kv7.5, a low-threshold noninactivating voltage-gated potassium channel, is preferentially targeted to excitatory endings of auditory neurons in the adult rat brainstem. Endbulds of Held from auditory nerve axons on the bushy cells of the ventral cochlear nucleus (VCN) and calyces of Held around the principal neurons in the medial nucleus of the trapezoid body (MNTB) are rich in KCNQ5 immunoreactivity.

'Green mice' display limitations in enhanced green fluorescent protein expression in retina and optic nerve cells.

Characterization of retinal cells, cell transplants and gene therapies may be helped by pre-labeled retinal cells, such as those transfected with vectors for green fluorescent protein expression. The aim of this study was to analyze retinal cells and optic nerve components from transgenic green mice (GM) with the 'enhanced' green fluorescent protein (EGFP) gene under the control of the CAG promoter (a chicken β-actin promoter and a cytomegalovirus enhancer). The structural analysis and electroretinography recordings showed a normal, healthy retina.

Hearing impairment in the P23H-1 retinal degeneration rat model.

The transgenic P23H line 1 (P23H-1) rat expresses a variant of rhodopsin with a mutation that leads to loss of visual function. This rat strain is an experimental model usually employed to study photoreceptor degeneration. Although the mutated protein should not interfere with other sensory functions, observing severe loss of auditory reflexes in response to natural sounds led us to study auditory brain response (ABR) recording.

Expression of calcium-binding proteins in layer 1 reelin-immunoreactive cells during rat and mouse neocortical development.

Cajal-Retzius cells in layer 1 of the developing cerebral cortex and their product of secretion, reelin, an extracellular matrix protein, play a crucial role in establishing the correct lamination pattern in this tissue. As many studies into reelin signaling routes and pathological alterations are conducted in murine models, we used double-labeling and confocal microscopy to compare the distribution of the cell-specific markers, calretinin and calbindin, in reelin-immunoreactive cells during postnatal rat and mouse neocortical development. In the rat, neither calretinin nor calbindin colocalized with reelin in Cajal-Retzius cells at P0-P2.

KCNQ5 reaches synaptic endings in the auditory brainstem at hearing onset and targeting maintenance is activity-dependent.

Kv7.5/KCNQ5, a voltage-dependent potassium channel that generates a subthreshold K+ current (also called M-current), is localized in excitatory endings of auditory brainstem nuclei in the adult rat. Here, we focus on how specific targeting develops from birth to adulthood in the rat.

The potassium channel KCNQ5/Kv7.5 is localized in synaptic endings of auditory brainstem nuclei of the rat.

KCNQ, also called Kv7, is a family of voltage-dependent potassium channels with important roles in excitability regulation. Of its five known subunits, KCNQ5/Kv7.5 is extensively expressed in the central nervous system and it contributes to the generation of M-currents.

Auditory nerve input is not an absolute requirement for the expression, distribution and calcium permeability of AMPA receptors in the adult rat ventral cochlear nucleus.

In order to understand whether glutamatergic excitatory presynaptic input is an absolute requirement for the adult regulation of postsynaptic glutamate receptors we analyzed if a period of 11 days of excitatory deprivation affects the expression, distribution and Ca(2+) permeability of AMPA receptor subunits in the ventral cochlear nucleus of the rat. Bilateral cochlear ablations were performed in 30-day-old rats. After 11 days of survival, immunohistochemistry for GluR1, GluR2/3 and GluR4 AMPA receptor subunits showed no changes in the normal pattern of distribution, with GluR2/3 and GluR4 immunoreactivity predominating, and little GluR1.

Developmental regulation and adult maintenance of potassium channel proteins (Kv 1.1 and Kv 1.2) in the cochlear nucleus of the rat.

The development and maintenance of the adult expression and distribution of Kv 1.1 and Kv 1.2, two voltage-dependent potassium channel subunits, were investigated in the anteroventral cochlear nucleus (AVCN) of the rat.

Expression and developmental regulation of the K+-Cl- cotransporter KCC2 in the cochlear nucleus.

KCC2 is a neuron-specific Cl- transporter whose role in adult central neurons is to maintain low intracellular Cl- concentrations and, therefore, generate an inward-directed electrochemical gradient for Cl- needed for the hyperpolarizing responses to the inhibitory amino acids GABA and glycine. We report that the KCC2 protein is intensely expressed in CN neurons and preferentially associated with plasma membrane domains, consistent with GABA and glycinergic-mediated inhibition in this auditory nucleus. Postnatal KCC2 expression and distribution patterns are similar in developing and adult CN neurons and do not match the time course of GABergic or glycinergic synaptogenesis.

Hormonal control of growth hormone secretion.

Growth hormone secretion by the somatotroph cells depends upon the interaction between hypothalamic regulatory peptides, target gland hormones and a variety of growth factors acting in a paracrine or autocrine fashion. This review will be focused on recent data regarding the mechanism by which growth hormone-releasing hormone (GHRH) influences somatotroph cell function and the physiological role played by Ghrelin and leptin in the regulation of growth hormone (GH) secretion. It is well established that binding of GHRH to its receptor leads to activation of protein kinase A (PKA).

A comparative study of protein kinase C-like immunoreactive cells in the retina.

The present study is a morphological and quantitative analysis of protein kinase C-like immunoreactive (PKC-L ir) bipolar cells in the retinas of five different vertebrate species (chicken, tench, zebrafish, goldfish and rat). The morphology of PKC-L-ir bipolar cell axon terminals in fish differs significantly from those of chicken and rat retinas. Fish have bulky terminals whereas chicken and rat have their terminals in the form of small knob-shaped branches.

Growing and regenerating axons in the visual system of teleosts are recognized with the antibody RT97.

We have analyzed the immunolabeling with the antibody RT97, a good marker for ganglion cell axons in several species, in the normal and regenerating visual pathways of teleosts. We have demonstrated that RT97 antibody recognizes several proteins in the tench visual system tissues (105, 115, 160, 200, 325 and 335 kDa approximately). By using immunoprecipitation and Western blot we have found that after crushing the optic nerve the immunoreactivity to anti RT97 increased markedly in the optic nerve.

Protein kinase C-like immunoreactive cells in embryo and adult chicken retinas.

Morphological evidence of a temporal parallelism between the appearance of the alpha isoform of protein kinase C (PKC) and some processes such as synaptogenesis in the plexiform layers of the chicken retina is offered. Immunostaining experiments were performed throughout embryonic, young and adult chicken life. The results help to understand the development of rod bipolar cells.

Enzyme histochemical identification of microglial cells in the retina of a fish (Tinca tinca).

Histochemistry for nucleoside diphosphatase was used to study the microglial cells in the adult tench retina. An abundant population of microglial cells was located in the vascular membrane, nerve fibre layer, inner and outer plexiform layers and scattered cells were observed in the inner nuclear layer. Rounded and amoeboid cells could be seen close to the vessel in the vascular membrane, bipolar cells in the nerve fibre layer and ramified cells in the rest of the layers.

Neurotrophins and their receptors in the tench retina during optic nerve regeneration.

To understand the role of neurotrophins in the visual system, we investigated the distribution of both neurotrophins and their receptors within the retina of a fish that has the capacity to spontaneously regenerate its optic nerve axons after lesion. Intact retinas and retinas from tench, whose optic nerve had been crushed, were analyzed by immunohistochemistry and in situ hybridization. Trk receptors were mainly immunolocalized in cells of the inner nuclear and ganglion cell layers, a distribution coincident with that of their mRNAs.

Increased levels of TrkA in the regenerating retinal ganglion cells of fish.

Retinal ganglion cells of the fish have the spontaneous capacity to regenerate after nerve crush, a phenomenon known to be facilitated by nerve growth factor (NGF). We have studied the high-affinity NGF receptor TrkA, during the regeneration of the tench (Tinca tinca L.) optic nerve, using immunocytochemical techniques.

Immunohistochemical distribution of neurotrophins and their receptors in the rat retina and the effects of ischemia and reperfusion.

1. Neurotrophins are molecules that regulate the survival, development and maintenance of specific functions in different populations of nerve cells. 2.

Diencephalic and mesencephalic structures related to the optic nerve organization in tench (Tinca tinca L., 1758). A study using fluoro-gold.

The location of several diencephalic and mesencephalic structures in the teleost fish, Tinca tinca, which have not been described previously, was made possible by injecting Fluoro-Gold, as an anterograde and retrograde tracer, into the optic nerve. In the pretectal area, we found the tractus opticus accessorius and the nucleus opticus dorsolateralis. We have made some specifications about the location and nomenclature of the branches belonging to the optic tracts and two nuclei also related to the visual system (the nucleus commissura posterior and the nucleus pretectalis periventricularis pars dorsalis).