Opioid receptor-like (ORL1) receptor distribution in the rat central nervous system: Comparison of ORL1 receptor mRNA expression with 125 I-[ 14 Tyr]-orphanin FQ binding

The recently discovered neuropeptide orphanin FQ (OFQ), and its opioid receptor-like (ORL1) receptor, exhibit structural features suggestive of the μ, κ, and δ opioid systems. The anatomic distribution of OFQ immunoreactivity and mRNA expression has been reported recently. In the present analysis, we compare the distribution of orphanin receptor mRNA expression with that of orphanin FQ binding at the ORL1 receptor in the adult rat central nervous system (CNS). By using in vitro receptor autoradiography with 125 I-[ 14 Tyr]-OFQ as the radioligand, orphanin receptor binding was analyzed throughout the rat CNS. Orphanin binding sites were densest in several cortical regions, the anterior olfactory nucleus, lateral septum, ventral forebrain, several hypothalamic nuclei, hippocampal formation, basolateral and medial amygdala, central gray, pontine nuclei, interpeduncular nucleus, substantia nigra, raphe complex, locus coeruleus, vestibular nuclear complex, and the spinal cord. By using in situ hybridization, cells expressing ORL1 mRNA were most numerous throughout multiple cortical regions, the anterior olfactory nucleus, lateral septum, endopiriform nucleus, ventral forebrain, multiple hypothalamic nuclei, nucleus of the lateral olfactory tract, medial amygdala, hippocampal formation, substantia nigra, ventral tegmental area, central gray, raphe complex, locus coeruleus, multiple brainstem motor nuclei, inferior olive, deep cerebellar nuclei, vestibular nuclear complex, nucleus of the solitary tract, reticular formation, dorsal root ganglia, and spinal cord. The diffuse distribution of ORL1 mRNA and binding supports an extensive role for orphanin FQ in a multitude of CNS functions, including motor and balance control, reinforcement and reward, nociception, the stress response, sexual behavior, aggression, and autonomic control of physiologic processes. J. Comp. Neurol. 412:563–605, 1999. © 1999 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34456/1/2_ftp.pd

New Mouse Lines for the Analysis of Neuronal Morphology Using CreER(T)/loxP-Directed Sparse Labeling

BACKGROUND: Pharmacologic control of Cre-mediated recombination using tamoxifen-dependent activation of a Cre-estrogen receptor ligand binding domain fusion protein [CreER(T)] is widely used to modify and/or visualize cells in the mouse. METHODS AND FINDINGS: We describe here two new mouse lines, constructed by gene targeting to the Rosa26 locus to facilitate Cre-mediated cell modification. These lines should prove particularly useful in the context of sparse labeling experiments. The R26rtTACreER line provides ubiquitous expression of CreER under transcriptional control by the tetracycline reverse transactivator (rtTA); dual control by doxycycline and tamoxifen provides an extended dynamic range of Cre-mediated recombination activity. The R26IAP line provides high efficiency Cre-mediated activation of human placental alkaline phosphatase (hPLAP), complementing the widely used, but low efficiency, Z/AP line. By crossing with mouse lines that direct cell-type specific CreER expression, the R26IAP line has been used to produce atlases of labeled cholinergic and catecholaminergic neurons in the mouse brain. The R26IAP line has also been used to visualize the full morphologies of retinal dopaminergic amacrine cells, among the largest neurons in the mammalian retina. CONCLUSIONS: The two new mouse lines described here expand the repertoire of genetically engineered mice available for controlled in vivo recombination and cell labeling using the Cre-lox system

Dopamine receptor localization in the mammalian retina.

After a short history of dopamine receptor discovery in the retina and a survey on dopamine receptor types and subtypes, the distribution of dopamine receptors in the retinal cells is described and correlated with their possible role in cell and retinal physiology. All the retinal cells probably bear dopamine receptors. For example, the recently discovered D1B receptor has a possible role in modulating phagocytosis by the pigment epithelium and a D4 receptor is likely to be involved in the inhibition of melatonin synthesis in photoreceptors. Dopamine uncouples horizontal and amacrine cell-gap junctions through D1-like receptors. Dopamine modulates the release of other transmitters by subpopulations of amacrine cells, including that of dopamine through a D2 autoreceptor. Ganglion cells express dopamine receptors, the role of which is still uncertain. M?r cells also are affected by dopamine. A puzzling action of dopamine is observed in the ciliary retina, in which D1- and D2-like receptors are likely to be involved in the cyclic regulation of intraocular pressure. Most of the dopaminergic actions appear to be extrasynaptic and the signaling pathways remain uncertain. Further studies are needed to better understand the multiple actions of dopamine in the retina, especially those that implicate rhythmic regulations

Immunohistochemical localization of GABA-containing neurons during postnatal development of the rat retina.

The localization of neurons containing gamma-amino-butyric acid (GABA)-immunoreactivity has been studied in the rat retina during postnatal development. Two populations of GABA-positive cells were observed. The first was located in the inner layers of the retina, with the number of cells and their immunoreactivity increasing during development until adulthood. Previous studies in adult rat enabled identification of these cells as a subpopulation of amacrine cells. The second was located in the outer layers of the retina. These cells displayed a transient GABA labelling, with no immunoreactivity detectable after postnatal day 15. Their localization and morphology corresponded to calbindin D-27kDa-positive horizontal cells. It was concluded that the transient GABA-positive cells were horizontal cells.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Molecular identification of a dopamine D1b receptor in bovine retinal pigment epithelium.

International audienceThe rhythmic daytime inhibition of phagocytosis of shed photoreceptor outer segments (OS) by the retinal pigment epithelium (RPE) is related to increased cAMP in RPE cells. Dopamine (DA), the light-adaptive signal of the retinal oscillator can activate adenylyl cyclase through its D1-like receptors. It reduces OS phagocytosis by cultured bovine RPE, but a DA receptor was not demonstrated. Using primers selected from alignment of D1-like receptor genes already cloned, we have amplified by PCR two sequences in bovine genomic DNA. Phylogenetic analysis demonstrated that they correspond to D1a and D1b receptors. These receptors were then searched for using the reverse transcription-polymerase chain reaction (RT-PCR) in cultured bovine RPE. Only the D1b receptor subtype was demonstrated. It could mediate the DA-induced inhibition of phagocytosis

Production of neurospheres from mammalian Müller cells in culture.

International audienceIn lower vertebrates, like fishes and amphibians, retina is able to self-regenerate whereas Mammalian retina has lost this property. Nevertheless, recently, it has turned out that retinal glial Müller cells were playing a role in neuronal regeneration of the adult rodent retina, in case of acute damages, by dedifferentiating and redifferentiating in glial and neural cells. The purpose of this study was to analyse the ability of mammalian Müller cells for forming neurospheres. First of all, rats Müller cells were isolated in a primary culture. Second, these cells were resuspended in two different culture media: the cells cultures in the Neurobasal-A medium kept a typical Müller cells morphology even after 15 days of EGF treatment, and the cells plated in the DMEM-F12 medium formed neurospheres from the third day in culture. The neurosphere cells expressed nestin, cellular retinaldehyde binding protein (CRALBP) and glial fibrillary acidic protein (GFAP). These results showed our capacity to isolate and propagate Müller cells-derived progenitor cells. Moreover, it allows us to control the number of progenitor cells and, in the future, to study their differentiation capacity

Recoverin and hippocalcin distribution in the lamprey (Lampreta fluviatilis) retina.

Recoverin is a calcium-sensing protein which is involved in the transduction of light in vertebrate photoreceptors. It is also detected in other retina cell types in which its function is not yet elucidated, and is an autoantigen in a cancer-associated degenerative disease of the retina. Recently, hippocalcin, an homologous protein of recoverin, belonging to the same family of fatty acylated EF-hand calcium binding proteins was described in mammals. The immunohistochemical studies presented in this paper demonstrate, that, in the retina of the lamprey, an Agnathan considered the living ancestor of actual jawed vertebrates, recoverin was present in all photoreceptors and, to a lesser extent in subpopulations of amacrine and ganglion cells whereas hippocalcin was detected in numerous amacrine and ganglion cells and in the inner segments of long photoreceptors. The existence of these calcium-binding proteins shows that they have a high degree of conservation during evolution. Their presence in the same cells that in jawed vertebrates (photoreceptors and ganglion cells for recoverin; amacrine and ganglion cells for hippocalcin) suggests that some retinal functions are well conserved but because they were also found in different cell types than in other species (amacrine for recoverin; photoreceptors for hippocalcin), they may have functions more specific to the lamprey retina.Comparative StudyJournal Articleinfo:eu-repo/semantics/publishe

Changes in retinal dopaminergic cells and dopamine rhythmic metabolism during the development of a glaucoma-like disorder in quails

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Human cord blood-derived hematopoietic and neural-like stem/progenitor cells are attracted by the neurotransmitter GABA.

International audienceMigration of stem/progenitor cells is a crucial event for homing toward tissue where cells need to be renewed. The neurotransmitter gamma-aminobutyric acid (GABA) has been shown to have a crucial role in migration of neuronal stem/progenitor cells. Since human umbilical cord blood (HUCB) contains stem/progenitor cells able to generate either neuronal or hematopoietic cells, we evaluated the effect of GABA on this type of cells. While whole fraction of mononuclear cells expressed GABA(A) and GABA(B) receptor subunits (GABA-R), only GABA(B)R subunits were found to be expressed on immature CD133+ cells. Functional experiments revealed that both cell fractions of HUCB were attracted by a gradient of GABA concentration and furthermore were blocked by specific antagonists of GABA(A)R and GABA(B)R bicuculline and saclofen, respectively. Moreover, through GABA(B)R activation the migrating fraction was highly enriched by both hematopoietic progenitors and cells able to generate neuron- like cells in culture. Therefore, GABA is a potent chemoattractant of HUCB stem/progenitor cells specifically through GABA(B)R activation