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E Normand

Publications and source records attributed to E Normand.

27 records · Page 2Linked to original sources
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

Simultaneous detection of two messenger RNAs in the central nervous system: a simple two-step in situ hybridization procedure using a combination of radioactive and non-radioactive probes.

We present here a method enabling the simultaneous detection of two messenger RNAs in tissue sections by use of a two-step in situ hybridization procedure. Tissue sections were hybridized with a radioactive probe and coated with emulsion. The emulsion was processed for development, fixed, and a second hybridization was performed through the emulsion with a biotinylated probe subsequently revealed with streptavidin-alkaline phosphatase. This procedure allows the detection of two mRNAs without loss of signal, removal of the emulsion, or spurious reaction. The simultaneous detection of oxytocin and vasopressin mRNAs in the hypothalamus, and of dopamine receptor and neuropeptide mRNAs in the striatum, demonstrated the efficiency of the procedure. Such a two-step procedure provides a simple and flexible way to make possible comparative analysis of the localization of two mRNAs within the same tissue section.

Animals↗
PubMed1990

Presence of neuropeptide messenger RNAs in neuronal processes.

The messenger RNAs coding for vasopressin, oxytocin, luteinizing hormone releasing-hormone and somatostatin have been detected in tissue sections of the rat brain, especially in the hypothalamus with radioactive and biotinylated oligonucleotide probes. The results demonstrate that neuropeptide mRNAs are present in the cytoplasm of cell bodies, in processes and in punctate structures in the vicinity of the cell bodies. These results demonstrate that neuropeptide mRNAs can be transported outside the cell body most probably in proximal dendrites but also in some of their branching, and possibly at synaptic contacts. These data suggest that neuropeptide mRNA could undergo a specific compartmentation that could contribute to the targetting of the corresponding peptide inside neurons.

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↗
PubMed1989

Distribution of CCK mRNA in particular regions (hippocampus, periaqueductal grey and thalamus) of the rat by in situ hybridization.

Cholecystokinin (CCK) mRNA was detected by in situ hybridization at high magnification in some rat brain regions where CCK octapeptide (CCK-8) is thought to produce its pharmacological effects. The labeling of the dentate gyrus and the sparse but intensively stained cells found in the CA1 layer, stratum radiatum and hilus could correspond to interneurons involved in hippocampal neural activity, in agreement with excitatory responses induced by local injection of CCK-8. The intense labeling of the Edinger-Westphal nucleus and more generally the presence of CCK mRNA in the periaqueductal gray and thalamus ventrobasal nuclei could account for the various effects of CCK in pain transmission.

Animals↗
PubMed1988

Dopaminergic neurons of the substantia nigra modulate preproenkephalin A gene expression in rat striatal neurons.

The messenger RNA coding for preproenkephalin A (PPA) was detected by in situ hybridization in striatal neurons in normal rats and in rats having had the right substantia nigra destroyed by an injection of 6-hydroxydopamine or by electrolysis. Animals were killed 15, 30, 45 and 70 days following the lesion. A double-stranded PPA cDNA and a single-stranded PPA cRNA labeled with 32P or 35S were used as probes to detect the PPA mRNA in brain sections. The controls demonstrated the specificity of the labeling. The darkening of X-ray film in contact with the striatum was appraised, the optical density was measured, and the density of the cells expressing the PPA gene in sections was calculated using an image analyzer. The mean number of silver grains per labeled cell (reflecting the number of PPA mRNA copies per cell) was also calculated using an image analyzer. The 6-hydroxydopamine lesion which destroyed all dopaminergic neurons in the right substantia nigra, provoked a large increase in the number of PPA mRNA copies in enkephalin neurons of the right striatum, and decreased the number of cells expressing the PPA mRNA in the left striatum. These variations substantia nigra provoked similar variations, but less intense.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Anatomical study of enkephalin gene expression in the rat forebrain following haloperidol treatment.

The effect of haloperidol treatment on preproenkephalin A (PPA) gene expression in the rat forebrain was anatomically studied by using an in situ hybridization procedure. The PPA mRNA was detected in sections of control rats and of rats having received an i.p. injection of haloperidol for 14 or 21 days. Sections were incubated with rat PPA cDNA labeled with 32P or 35S, exposed with X-ray film and dipped in Ilford K-5 emulsion. The results showed that haloperidol treatment did not modify the number of cells expressing the PPA gene in the caudate-putamen, the nucleus accumbens, the septum and the olfactory tubercle. In contrast, the PPA mRNA content was increased in the neurons of the caudate-putamen and nucleus accumbens, but unchanged in other areas. These results demonstrate that haloperidol acts by increasing PPA mRNA content selectively in striatal neurons already expressing the PPA gene.

Animals↗
PubMed1986

In situ hybridization histochemistry for the analysis of gene expression in the endocrine and central nervous system tissues: a 3-year experience.

We report our experience in development of the in situ hybridization (ISH) procedure to detect messenger RNAs (mRNAs) coding for various molecules involved in endocrine glands and central nervous system activity, including mRNAs coding for endorphin precursors [preproenkephalin A (PPA), pro-opiocortin (POMC)], vasopressin, and transferrin. Various conditions of fixation and handling of the tissues were tested to establish optimal parameters for mRNA detection. Double-stranded DNA probes labeled by nick translation, synthetic oligonucleotides labeled at their 5' end, as well as single-stranded RNA probes were used, after incorporation of 32P- or 35S-labeled nucleotides. Specific requirements for efficient and reproducible ISH investigations are discussed. Cells expressing the PPA gene in the adrenal medulla and in the brain were detected by ISH. The results show that ISH is as sensitive as immunohistochemistry in detecting peptide-producing cells in the adrenal and that it allows detection of PPA cell bodies in brain in conditions in which they are inconstantly detected by immunohistochemistry. Unilateral destruction of substantia nigra provokes a dramatic decrease in the number of neurons expressing the PPA gene in the contralateral striatum. Cells expressing the POMC gene were detected in the pituitary of various species including man and in the rat arcuate nucleus. Neurons containing vasopressin mRNA were visualized in the supraoptic paraventricular and suprachiasmatic nucleus of the adult rat by using a synthetic oligonucleotide probe. Transferrin gene expression was shown in the central nervous system of the rat brain in two cell populations, the oligodendrocytes and the epithelial cells of the choroid plexus, by demonstration of simultaneous presence in them of transferrin immunoreactivity together with transferrin mRNA. These results show that the ISH procedure is a technique that can be routinely used to investigate gene transcription anatomically in complex heterocellular tissues such as the endocrine glands and the nervous system.

Adrenal Medulla↗