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C Le Moine

Publications and source records attributed to C Le Moine.

33 records · Page 2Linked to original sources
PubMed1995

D1 and D2 receptor gene expression in the rat frontal cortex: cellular localization in different classes of efferent neurons.

The dopaminergic input to the frontal cortex has an important role in motor and cognitive functions. These effects are mediated by dopamine receptors both of type D1 and of type D2, although the neural circuits involved are not completely understood. We used in situ hybridization to determine the cellular localization of D1 and D2 receptor mRNAs in the rat frontal cortex. Retrograde tracing was used in the same animals to identify the main cortical efferent populations. Fluorogold was injected into the different cortical targets of the frontal cortex and sections were hybridized with D1 and D2 35S-labelled cRNA probes. D1 and D2 mRNA-containing neurons were present in all the cortical areas investigated, with greater expression in the medial prefrontal, insular and cingulate cortexes and lower expression in the motor and parietal cortexes. Neurons containing D1 mRNA were most abundant in layer VIb; they were also present in layers VIa and V of all cortical layers and in layer II of the medial prefrontal, cingulate and insular areas. Double labelling with fluorogold demonstrated that D1 mRNA was present in corticocortical, corticothalamic and corticostriatal neurons. Neurons containing D2 mRNA were essentially restricted to layer V, but only in corticostriatal and corticocortical neurons. Neither D1 nor D2 mRNA was found in corticospinal or corticopontine neurons. The present results demonstrate that D1 and D2 receptor genes are expressed in efferent cortical populations, with higher expression for D1. In spite of an overlap in some cortical layers, the expression of D1 and D2 receptor genes is specific for different categories of pyramidal neurons.

Animals↗
PubMed1995

Ontogeny of the D1 dopamine receptor in the rat striatonigral system: an immunohistochemical study.

Antibodies were raised against a recombinant protein to analyse the pre- and postnatal ontogeny of the neurons expressing the D1 dopamine receptor in the striatum by immunohistochemistry. We report that D1 immunoreactivity is detectable from gestational day (G) 15 and is distributed homogeneously throughout the striatum from G15 to G18. From G19-20 to postnatal day (P) 3, D1 immunoreactivity becomes heterogeneous and predominates in cell bodies of the patch compartment while very limited immunoreactivity is detectable in the matricial compartment. The differential intensity between patches and matrix reaches its peak around P0. From P2, the pattern of D1 immunoreactivity progressively assumes the homogeneous distribution characteristic of the adult striatum. The expression of D1 mRNA in striatal neurons, as investigated by in situ hybridization, displays a similar pattern during this period. Substance P mRNA is also preferentially expressed in the patch compartment during the same period. D1 immunoreactivity appears at G17 in the substantia nigra as clusters of fibres and increases subsequently until reaching its adult form during the first postnatal week. These results demonstrate that the two compartments of the developing striatum display differential transcriptional and translational activity for the D1 gene and consequently two different and successive patterns of expression of D1 protein: patch neurons first express D1 receptor intensely while matrix neurons express it later and in smaller amounts so that D1 receptor appears transiently during the perinatal period as a marker of the patch compartment.

Animals↗
PubMed1995

Localization of dopamine D2 receptor mRNA in glomus cells of the rabbit carotid body by in situ hybridization.

The localization of mRNA coding for the dopamine D2 receptor was studied in the rabbit carotid body using in situ hybridization with synthetic 35S-labelled oligodeoxynucleotides. Using autoradiography on cryostat or semi-thin sections, labelling was observed over the cytoplasm of glomus cells, but not over sustentacular cells. A quantitative study showed that labelling intensity (silver grain density) was increased by haloperidol treatment. These results suggest that glomus cells express the dopamine D2 receptor gene and that this expression is regulated.

Animals↗
PubMed1995

Use of non-radioactive probes for mRNA detection by in situ hybridization: interests and applications in the central nervous system.

Non-radioactive probes for in situ hybridization (ISH) are now widely used to detect mRNAs in the central nervous system (CNS) using light and electron microscopy. Many different protocols for the detection of biotinylated or digoxigenin-labelled probes are now available. The advantages and inconveniences of the use of the non-radioactive probes are reviewed in the current work. These aspects are illustrated by some results from first-hand experience in the field of ISH to analyse gene expression and neuronal phenotypes in the hypothalamus and the basal ganglia. A very sensitive procedure for the simultaneous detection of two mRNAs with cRNA probes have been detailed and using in particular digoxigenin-labelled probes.

Animals↗
PubMed1994

Delta-opioid receptor gene expression in the mouse forebrain: localization in cholinergic neurons of the striatum.

Opioid peptides and opioid receptors, particularly the delta receptor, are abundant in the striatum where they contribute to the neuronal interactions, and are involved in various behavioral effects. The recent cloning of the delta-opioid receptor now allows the identification of the striatal neurons that express it, and that are direct targets of endogenous opioid peptides such as enkephalins. In this context, we have used in situ hybridization histochemistry to determine the distribution of the delta-opioid receptor messenger RNA in the forebrain, and especially the phenotype of the neurons expressing the delta-opioid receptor gene in the striatum. We show that the topgraphy of the neurons containing the delta-opioid receptor messenger RNA is similar to the topography of the neurons containing the choline acetyltransferase messenger RNA in the mouse forebrain. Comparison of adjacent serial sections demonstrates that the delta-opioid receptor gene is indeed expressed exclusively in cholinergic interneurons in the striatum. As these neurons also selectively express the substance P receptor gene, our data suggest that the striatal cholinergic interneurons are a common link in the interactions between the two striatal efferent populations, namely enkephalin and substance P neurons.

Animals↗
PubMed1992

RHS2, a POU domain-containing gene, and its expression in developing and adult rat.

Gene expression within the central nervous system is regulated by complex interactions of DNA-binding proteins, among which are the POU domain-containing proteins, which are distantly related to homeobox proteins. These POU domain-containing proteins have been implicated in control of transcription and replication within the central nervous system. We used degenerate primers with the PCR to isolate another POU domain-containing cDNA, RHS2, from hypothalamic RNA. Isolation of a putative full-length cDNA was accomplished by using serial dilutions of a hypothalamic cDNA library grown on solid medium. This member of the class III POU family is expressed in rats from embryonic day 11.5 into adulthood, being especially prominent in the brain. We performed double-labeling hybridization histochemistry and determined that RHS2 is coexpressed with a variety of neuropeptides in medium-sized neurons in the caudate putamen and with dynorphin in the paraventricular and supraoptic nuclei of the hypothalamus. Expression of RHS2 in the caudate putamen was increased by elimination of its nigrostriatal dopaminergic innervation.

Aging↗
PubMed1991

Phenotypical characterization of the rat striatal neurons expressing the D1 dopamine receptor gene.

In situ hybridization experiments were performed in rat brain sections from normal and 6-hydroxydopamine-treated rats in order to map and identify the neurons expressing the D1 receptor gene in the striatum and the substantia nigra. Procedures of combined in situ hybridization, allowing the simultaneous detection of two mRNAs in the same section or in adjacent sections, were used to characterize the phenotypes of the neurons expressing the D1 receptor gene. D1 receptor mRNA was found in neurons all over the caudate-putamen, the accumbens nucleus, and the olfactory tubercle but not in the substantia nigra. In the caudate-putamen and accumbens nucleus, most of the neurons containing D1 receptor mRNA were characterized as medium-sized substance P neurons and distinct from those containing D2 receptor mRNA. Nevertheless, 15-20% of the substance P neurons did not contain D1 receptor mRNA. The neurons containing preproenkephalin A mRNA did not contain D1 receptor mRNA but contained D2 receptor mRNA. A small number of cholinergic and somatostatinergic neurons exhibited a weak reaction for D1 receptor mRNA. These results demonstrate that dopamine acts on efferent striatal neurons through expression of distinct receptors--namely, D1 and D2 in separate cell populations (substance P and preproenkephalin A neurons, respectively)--and can also act on nonprojecting neurons through D1 receptor expression.

Animals↗
PubMed1991

Rat striatal and mesencephalic neurons contain the long isoform of the D2 dopamine receptor mRNA.

Cloning of the D2 dopamine receptor gene has demonstrated that two D2 mRNA isoforms are generated through alternative splicing: a short mRNA (D2(415)) and a long one (D2(444)) that differs by an additional exon transcript. D2 receptor gene expression was demonstrated in striatal dopamine terminal fields as well as in the mesencephalon by in situ hybridization using a probe that does not differentiate the two isoforms or a probe specific for the D2(444)) mRNA. We report here that the long D2(444)) mRNA isoform is present in all the neurons expressing the D2 receptor gene in the striatum and the mesencephalon. In the striatum, medium-sized neurons (previously identified as enkephalinergic) and large-sized neurons (previously identified as cholinergic) contain the D2(444)) mRNA. Our results with the D2(444)) probe confirm that 20% of the cholinergic neurons in the striatum do not express the D2 gene. The present results also demonstrate that the neurons expressing the D2 receptor gene in the substantia nigra are dopamine neurons and that D2 mRNA can be present in proximal dendrites.

Animals↗
PubMed1991

Striatal neurons express increased level of dopamine D2 receptor mRNA in response to haloperidol treatment: a quantitative in situ hybridization study.

In the present study, quantitative in situ hybridization was used to analyse the effect of haloperidol treatment on D2 dopamine receptor gene expression in the rat caudate-putamen nucleus. Variations of D2 receptor mRNA level were studied and measured at the macroscopic level of densitometric analysis of X-ray film and at the microscopic level by counting of autoradiographic silver grains in striatal cells. Macroscopic analysis demonstrated that haloperidol treatment two times 1 mg/kg per day during seven, 14 and 21 days increased D2 receptor mRNA level in the caudate-putamen. Detailed microscopic analysis demonstrated a significant increase in D2 receptor mRNA in the two neuronal populations known to express the D2 receptor gene: medium-sized neurons previously identified as enkephalinergic neurons, and large-sized neurons previously identified as cholinergic neurons. The increase was more important in cholinergic neurons (+119%) than in enkephalinergic neurons (+54%). Haloperidol treatment did not modify the number of medium-sized enkephalinergic neurons expressing the D2 receptor mRNA. In contrast, it significantly increased the percentage of large-sized neurons containing D2 receptor mRNA (from 80 to 94%). These results demonstrate that haloperidol treatment acts at the gene level to modulate D2 receptor content in striatal dopaminoceptive neurons, and that the D2 receptor mRNA increase in postsynaptic neurons contributes to dopamine supersensitivity induced by neuroleptics in the rat. This suggests that dopamine acts trans-synaptically to control D2 receptor gene expression in target striatal neurons. These results suggest that modifications of D2 receptor gene expression may be part of the biological events that lead to the movement disorders induced by neuroleptic drugs or Parkinson's disease.

Animals↗
PubMed1990

D2 dopamine receptor gene expression by cholinergic neurons in the rat striatum.

In situ hybridization with D2 receptor probe and immunohistochemistry with choline acetyltransferase (ChAT) antibody performed on adjacent sections demonstrate dopamine D2 receptor gene expression in cholinergic neurons of the rat caudate-putamen and nucleus accumbens. Eighty per cent of cholinergic neurons in the striatum contain detectable D2 receptor mRNA. The other neurons without detectable D2 mRNA do not display specific localization or aspect in the caudate-putamen and nucleus accumbens as compared to the other cholinergic neurons. The absence of detectable D2 mRNA in certain cholinergic neurons can be due to the limited sensitivity of the procedure that would not detect low mRNA levels, or alternatively can reflect the existence of two cholinergic cell populations in the striatum, one of which would not express the D2 receptor gene. The other forebrain cholinergic neurons do not contain D2 mRNA.

Animals↗
PubMed1990

Dopamine receptor gene expression by enkephalin neurons in rat forebrain.

In situ hybridization experiments were performed with brain sections from normal, control and haloperidol-treated rats to identify and map the cells expressing the D2 dopamine receptor gene. D2 receptor mRNA was detected with radioactive or biotinylated oligonucleotide probes. D2 receptor mRNA was present in glandular cells of the pituitary intermediate lobe and in neurons of the substantia nigra, ventral tegmental area, and forebrain, especially in caudate putamen, nucleus accumbens, olfactory tubercle, and piriform cortex. Hybridization with D2 and preproenkephalin A probes in adjacent sections, as well as combined hybridization with the two probes in the same sections, demonstrated that all detectable enkephalin neurons in the striatum contained the D2 receptor mRNA. Large neurons in caudate putamen, which were unlabeled with the preproenkephalin A probe and which may have been cholinergic, also expressed the D2 receptor gene. Haloperidol treatment (14 or 21 days) provoked an increase in mRNA content for D2 receptor and preproenkephalin A in the striatum. This suggests that the increase in D2 receptor number observed after haloperidol treatment is due to increased activity of the D2 gene. These results indicate that in the striatum, the enkephalin neurons are direct targets for dopamine liberated from mesostriatal neurons.

Animals↗
PubMed1969

[Curettage].

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Humans↗