Influence of preoperative hydronephrosis on the outcome of urothelial carcinoma of the upper urinary tract after nephroureterectomy: the results from a multi-institutional French cohort.

OBJECTIVES: Recent publications have assessed the prognostic significance of hydronephrosis in the outcome of upper tract urothelial carcinoma (UUT-UC). Our study sought to determine the prognostic impact of hydronephrosis on UUT-UC survival and its relationship to the clinicopathological features. MATERIALS AND METHODS: A retrospective, multi-institutional French study was conducted on 401 patients who underwent radical nephroureterectomy for non-metastatic UUT-UC. Hydronephrotic status was determined using preoperative imaging reports. Univariate and multivariate analyses were conducted to identify factors associated with survival. RESULTS: Preoperative hydronephrosis was present in 74 patients. Median follow-up was 26 months. Hydronephrosis was associated only with ureteral localisation (p < 0.001). No difference was observed in 5-year cancer-specific survival (CSS) between the hydronephrosis group (80.1 %) and the no hydronephrosis group (83.6 %) (p > 0.05). Only age (p = 0.02) and pT stage (p = 0.01) were independent predictors of CSS. Hydronephrosis was not a significant predictor of CSS in the univariate and multivariate analyses (p = 0.87 and p = 0.66). No significant difference was observed for 5-year metastasis-free survival (MFS) between the hydronephrosis group (69.8 % ± 6.6 %) and the no hydronephrosis group (80.5 % ± 3 %) (p = 0.052). Hydronephrosis was not a significant predictor of MFS in the univariate and multivariate analyses (p = 0.16 and p = 0.36). Multifocality (p = 0.02), pT stage (p < 0.001) and positive surgical margins (p = 0.02) were independent predictors of MFS. For the pelvic tumours subgroup, hydronephrosis was an independent predictor of MFS (p = 0.01) but not CSS (p = 0.86). CONCLUSION: Preoperative hydronephrosis was not associated with survival. However, among tumours presenting with hydronephrosis, pelvicalyceal tumours appear to have a worse prognosis than ureteral tumours.

[Preoperative assessment of renal vascular anatomy for donor nephrectomy: Is CT superior to MRI?]. / Évaluation préopératoire du nombre de vaisseaux chez le donneur de rein vivant. La TDM est-elle supérieure à l'IRM ?

BACKGROUND: computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are both used in the preoperative assessment of vascular anatomy before donor nephrectomy. Our objective was to determine retrospectively and to compare the sensitivity of CTA and MRA imaging in preoperative renal vascularisation in living kidney donors. PATIENTS AND METHODS: between 1999 and 2007, 42 kidney donors were assessed in our center: 27 by MRA, 10 by CTA, and five by both techniques. Images were interpreted using multiplanar reconstructions. Results were compared retrospectively with peroperative findings; discordant cases were re-examined by an experienced radiologist. Numbers of vessels detected with imaging methods was compared with numbers actually found at the operating time. RESULTS: MRA showed 35/43 arteries (Se 81.4 %) and 33/34 veins (Se 97.1 %), and CTA showed 18/18 arteries (Se 100 %) and 15/16 veins (Se 93.8 %). The presence of multiple arteries was detected in only one third of cases (3/9) on MRI scans; this difference was statistically significant. The missed arteries were not detected on second examination of the MRI scans with the knowledge of peroperative findings. CONCLUSION: MRA is less sensitive than CTA for preoperative vascularisation imaging in living renal donors, especially in the detection of multiple renal arteries.

Acute ethanol induces Fos in GABAergic and non-GABAergic forebrain neurons: a double-labeling study in the medial prefrontal cortex and extended amygdala.

The purpose of this study was to further address the hypothesis that ethanol activates GABAergic neurons in specific brain neurocircuits that mediate motivated behavior and control of action, such as the central extended amygdala and medial prefrontal cortex. Male Sprague-Dawley rats received habituation to 7 days of daily intragastric administration of water (5 ml/kg) followed by a single acute intragastric dose of ethanol (2.5 g/kg) or water then, 2 h later, by paraformaldehyde perfusion. Rats left undisturbed in the animal room throughout the experiment were also perfused (naive group). Brain sections were processed for single Fos immunohistochemistry or dual Fos immunohistochemistry/glutamic acid decarboxylase (GAD) mRNA in situ hybridization. Intragastric water administration increased the number of Fos-immunoreactive cells in the infralimbic cortex and lateral part of the central nucleus of the amygdala compared with the naive group. Ethanol administration increased the number of Fos-immunoreactive cells in the infralimbic (+57.5%) and prelimbic (+105.3%) cortices, nucleus accumbens shell region (+88.2%), medial part of the central nucleus of the amygdala (+160%), and lateral part of the bed nucleus of the stria terminalis (+198.8%) compared with the water-treated group. In the nucleus accumbens shell region, central nucleus of the amygdala, and bed nucleus of the stria terminalis, more than 80% of Fos-immunoreactive neurons were GABAergic after ethanol administration. In contrast, in the prelimbic cortex, 75% of Fos-immunoreactive neurons were not GABAergic. These results constitute new evidence for region-specific functional interactions between ethanol and GABAergic neurons.

Large discrepancies in cellular distribution of the tonicity-induced expression of osmoprotective genes and their regulatory transcription factor TonEBP in rat brain.

Osmoprotective genes are tonicity-activated genes involved in cellular osmoadaptation to hypertonicity and considered to be regulated by a specific transcription factor called tonicity-responsive enhancer-binding protein (TonEBP). In the brain we had previously established that TonEBP was expressed and tonicity-induced in neurons only. Here we have compared in various brain regions of rats subjected to systemic hypertonicity, the cellular expression of TonEBP through immunocytochemistry and the cellular expression of osmoprotective genes, namely aldose reductase (AR), sodium-dependent myo-inositol transporter (SMIT), betaine/GABA transporter (BGT1) and taurine transporter (TauT), by in situ hybridization using non-radioactive digoxigenin-labeled riboprobes. In neurons where TonEBP was strongly tonicity-induced, AR-mRNA labeling was strongly increased in some subsets (e.g. hippocampus pyramidal cells, cerebellar Purkinje cells and neurons of the hypothalamic magnocellular nuclei) but remained undetectable in some other subsets (e.g. neurons in cerebral cortex). Tonicity-induced AR-mRNA labeling was observed only several hours after the tonicity-induced expression of TonEBP. SMIT-mRNA labeling was tonicity-induced as densely and evenly distributed dots in neuron poor regions (e.g. cerebral cortex layer I and hippocampus stratum lacunosum-moleculare). The tonicity-induced expression of SMIT-mRNA may thus occur in non-neuronal cells, presumably astrocytes, where TonEBP is neither significantly expressed, nor tonicity-induced. In neurons showing a strong tonicity-induced expression of TonEBP, no SMIT-mRNA labeling was observed. BGT1-mRNA and TauT-mRNA labeling could not be detected, even after systemic hypertonicity. The present work reveals large discrepancies between the cellular distribution of the tonicity-induced expression of osmoprotective genes and that of their regulatory transactivator TonEBP. Depending on the cell subsets and the osmoprotective genes, TonEBP may appear insufficient or conversely unnecessary for the tonicity-induced activation of an osmoprotective gene. Altogether our results show that brain cells, even from the same class, activate distinct osmoprotective genes through distinct activation processes to adapt to hypertonicity.

Neurotensin receptor expression in the rat forebrain and midbrain: a combined analysis by in situ hybridization and receptor autoradiography.

The aim of the present study was to examine the distribution of the levocabastine-insensitive high-affinity neurotensin binding sites in the rat forebrain and midbrain in relation to the distribution of the cloned neurotensin receptor mRNA by using a combination of both high-resolution in vitro receptor autoradiography and in situ hybridization approaches. Groups of cells rich in neurotensin receptor mRNA were observed in the basal forebrain nuclei, the ventral tegmental area, the substantia nigra and in the interfascicular and caudal linear nuclei and the retrorubral field. Cells expressing lower levels of neurotensin receptor mRNA were found in several subdivisions of the cortex; the dentate gyrus; the septofimbrial, suprachiasmatic, medial habenular, and mammillary nuclei; the dorsal part of the lateral septum; the zona incerta; and the dorsomedial and perifornical hypothalamic areas. Most of the brain areas containing neurotensin receptor mRNA demonstrated a selective association of neurotensin binding sites with neuronal cell bodies. In contrast, in several telencephalic and diencephalic structures, the presence of neurotensin binding sites was not correlated with that of neurotensin receptor mRNA, suggesting that neurotensin receptors were mainly located on axon terminals. This study provides a better understanding of the anatomical organization of neurotensin receptor expressing systems in the rat brain and gives further insight into the pre- vs. postsynaptic location of neurotensin receptors in various brain regions. Moreover, it indicates that all neurons expressing the cloned neurotensin receptor harbour neurotensin binding sites on their perikaryal membrane.

Periventricular dopaminergic neurons terminating in the neuro-intermediate lobe of the cat hypophysis.

The aim of the present study was to determine the exact origins of the dopaminergic hypothalamohypophyseal projections in the cat brain. For this purpose, we used a retrograde tracer technique with horseradish peroxidase (HRP) in conjunction with tyrosine hydroxylase (TH) immunohistochemistry as a marker for the dopaminergic neurons. After injections of the tracer into the neuro-intermediate lobe, a substantial number of HRP-labeled neurons was observed in the supraoptic and paraventricular neurosecretory nuclei. Furthermore, a cluster of HRP-positive neurons was found in the tuberal component of the periventricular nucleus where few, if any, neurosecretory magnocellular cells are identified. TH immunohistochemistry on the same sections further revealed that virtually all these HRP-containing neurons showed TH immunoreactivity. These double-labeled neurons were medium in size and fusiform or ovoid and appeared to belong to the A14 dopamine cell group. In addition to these medium-sized double-labeled neurons, a magnocellular type of double-labeled cell body was identified just adjacent to the organum vasculosum of the lamina terminalis and in and around the supraoptic and paraventricular nuclei. These double-labeled cells appeared to be members of the A14 and A15 dopamine cell groups. In conclusion, the present study indicated that the dopaminergic projections to the cat neurointermediate lobe might originate mainly in the medium-sized cells located in the tuberal periventricular nucleus and partly in the large-sized cells located in and around the supraoptic and paraventricular neurosecretory nuclei.

Localization of tyrosine hydroxylase-immunoreactive neurons in the cat hypothalamus, with special reference to fluorescence histochemistry.

The present study examines the distribution and morphological characteristics of neurons containing immunoreactivity of tyrosine hydroxylase in the cat hypothalamus. We used the indirect immunoperoxidase technique on vibratome sections. Tyrosine hydroxylase-immunoreactive cell bodies were widely distributed in discrete regions of the cat hypothalamus. Several principal cell groups were identified. They were seen in the posterior and dorsal hypothalamic areas, zona incerta, dorsomedial and lateral hypothalamic areas, arcuate nucleus, periventricular nucleus, paraventricular nucleus, and an area of the tuber cinereum and preoptic area. These cells presented two different morphological characteristics; small with two to three short processes and medium to large, multipolar with three to five long dendritic trees. The atlas is presented in twelve cross-sectional drawings of the cat hypothalamus from the level A8.5 to A15 of the Horsley-Clarke stereotaxic planes. We also examined the distribution of hypothalamic catecholamine fluorescent neurons by using the aqueous aldehyde method in combination with glyoxylic acid applied to vibratome sectioned tissues, which improves sensitivity. Comments are made on the relative localizations of the tyrosine hydroxylase-immunoreactive and aldehyde-induced histofluorescent cells, as well as on species differences between the cat, rat, and mouse.

An immunohistochemical study of the organization of catecholaminergic cells and terminal fields in the paraventricular and supraoptic nuclei of the hypothalamus.

The distribution of catecholaminergic fibers and cell bodies in the paraventricular and supraoptic nuclei of the hypothalamus was investigated with immunohistochemical methods in the adult albino rat. Sections through the nuclei were stained with antisera to the catecholamine synthesizing enzymes tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH), and phenylethanolamine-N-methyltransferase (PNMT). The results suggest that adrenergic (PNMT-stained) fibers innervate the entire parvocellular division of the paraventricular nucleus, although the highest density of fibers was found in the medial part of the division. Only widely scattered adrenergic fibers are found in the magnocellular division of the nucleus and in the supraoptic nucleus. Noradrenergic fibers appear to innervate the periventricular zone of the paraventricular nucleus and those parts of the paraventricular and supraoptic nuclei that contain predominantly vasopressinergic neurons in both the normal and in the homozygous Brattleboro rat. Significant numbers--somewhat more than 500--of dopaminergic (TH-stained) neurons are found in the paraventricular nucleus; the cells are distributed throughout the nucleus but are concentrated in the medial and periventricular parts of the parvocellular division. Double-labeling experiments with the retrogradely transported tracer true blue indicate that between 4% and 8% of the dopaminergic neurons in the paraventricular nucleus project to the region of the dorsal vagal complex and/or thoracic levels of the spinal cord. It is concluded that adrenergic inputs to the paraventricular nucleus may influence cells that project to the median eminence and to preganglionic autonomic cell groups in the medulla and spinal cord. Noradrenergic inputs to the supraoptic and paraventricular nuclei may influence primarily vasopressinergic cells that project to the posterior lobe of the pituitary, as well as cells in the periventricular part of the paraventricular nucleus that project to the median eminence.

Distribution of cells expressing vasoactive intestinal peptide/peptide histidine isoleucine-amide precursor messenger RNA in the rat brain.

The distribution of cells expressing vasoactive intestinal peptide/peptide histidine isoleucine-amide precursor messenger RNA was investigated in the rat brain and pituitary by in situ hybridization using a synthetic 35S-labeled oligonucleotide probe. Detection of labeled neurons by light-microscopic radioautography revealed a selective repartition of the messenger RNA-expressing cells. Several major vasoactive intestinal peptide/peptide histidine isoleucine-amide messenger RNA-containing cell groups were demonstrated including layers II-VI of the cerebral cortex, the suprachiasmatic nucleus and various thalamic structures such as the ventrolateral, posterior, lateral reticular, paracentralis and gelatinosus nuclei. Positive cells, to a lesser extent, were also found in the limbic system, medial preoptic area, superior and inferior colliculi as well as in the central gray matter. They were totally absent in the pituitary and the pineal gland of normal rats. The results of the present study provide a detailed mapping of neurons expressing vasoactive intestinal peptide/peptide histidine isoleucine-amide messenger RNA in the adult rat brain. The predominance of vasoactive intestinal peptide/peptide histidine isoleucine-amide messenger RNA-containing neurons in the cerebral cortex, suprachiasmatic nucleus and thalamus suggest that vasoactive intestinal peptide is mainly involved in the control of cortical informations, circadian rhythms and sensory perception in agreement with several physiological data.

Glutamate decarboxylase-immunoreactive boutons in synaptic contacts with hypothalamic dopaminergic cells: a light and electron microscopy study combining immunocytochemistry and radioautography.

Double post-embedding immunolabeling of both tyrosine hydroxylase and glutamate decarboxylase on 1-micron semi-thin sections allowed the visualization of numerous endings that use gamma-aminobutyrate as a transmitter apposed to dopaminergic cell bodies in the periventricular-arcuate hypothalamic complex. Up to fifteen glutamate decarboxylase-positive contacts per tyrosine hydroxylase-positive cell profile could be observed. In some favourable planes of section glutamate decarboxylase-positive endings were also seen in close apposition to proximal dopaminergic dendrites. About 250 tyrosine hydroxylase-positive cell profiles, whose diameter approached the maximum diameter of the dopaminergic cells, were surveyed. An average of 7.4 glutamate decarboxylase-positive contacts were counted on these profiles. From these figures it was estimated that a dopaminergic cell body was contacted on average by 75-175 terminals that use gamma-aminobutyrate as a transmitter. At the electron-microscopic level, the nature of these contacts was investigated by a method combining radioautographic detection of cell bodies having taken up tritiated dopamine and pre-embedding immunostaining of glutamate decarboxylase containing endings. Glutamate decarboxylase-positive axon terminals were seen apposed to somatic and dendritic elements. On some favorable planes of section, they were found to be engaged in morphologically defined synaptic complexes of the symmetrical or asymmetrical type. A number of the postsynaptic perikarya were labelled by tritiated dopamine and, in agreement with the light microscopic observations, they were frequently seen in contact with more than one immunopositive ending. The present findings provide a morphological substratum for a direct gamma-aminobutyrate control of the tuberoinfundibular dopaminergic neurons. Such a control could account more particularly for the central, stimulatory effects of gamma-aminobutyrate on prolactin secretion.

Neurons of origin of the neurotensinergic plexus enmeshing the ventral tegmental area in rat: retrograde labeling and in situ hybridization combined.

The morphological and physiological substrates that underlie the mutual regulatory interactions of neurotensin and dopamine in the rat mesotelencephalic projections and related structures remain to be fully described. A salient candidate for neurotensinergic effects on the mesotelencephalic dopamine projection is the dense plexus of neurotensin immunoreactive axons that enmeshes the ventral tegmental area and substantia nigra, but the locations of the neurons that give rise to this plexus have not been identified and its systemic context remains obscure. To address this, Fluoro-Gold and the cholera toxin beta subunit, retrogradely transported axonal tracers, were injected into the ventral tegmental area of rats and the brains were processed to demonstrate neurons that contained both retrograde tracer immunoreactivity and a probe against neurotensin/neuromedin N messenger RNA. Substantial numbers of double-labeled neurons were observed in the rostral part of the lateral septum, and in a region centered on the shared boundaries of the bed nucleus of stria terminalis, ventromedial ventral pallidum, diagonal band of Broca, lateral preoptic area and rostral lateral hypothalamus. A few double-labeled neurons were also observed in the dorsal raphe nucleus and adjacent periaqueductal gray. Despite the administration of haloperidol and D-amphetamine to elicit and enhance neurotensin/neuromedin N messenger RNA expression in striatum, including the nucleus accumbens and olfactory tubercle, no double-labeled neurons were observed there. These results identify a novel brain substrate for control of midbrain dopamine levels, which affect reward mechanisms and motivation.

Localization of substance P- and enkephalin-like immunoreactivity in relation to catecholamine-containing cell bodies in the cat dorsolateral pontine tegmentum: an immunofluorescence study.

The distribution of tyrosine hydroxylase-, substance P- and enkephalin-immunoreactive neurons in the cat dorsolateral pons was studied using the indirect immunofluorescence method of Coons. To allow for the visualization of substance P- and enkephalin-immunoreactive cell bodies, colchicine was injected either in the ventricular space or in the cerebral tissue. The distribution of the tyrosine hydroxylase-immunoreactive cell bodies corresponded with the well-known distribution of catecholamine cells in this area of the brain. The observation of adjacent sections treated separately with tyrosine hydroxylase- and enkephalin-antiserum revealed that most catecholaminergic cells contain enkephalin-immunoreactivity. In addition to this catecholamine-enkephalin cell population, a moderate number of substance P-immunoreactive cell bodies was found in dorsolateral pons. The peribrachial nuclei were found to be densely supplied with substance P- and enkephalin-immunoreactive fibers, whereas the medial subdivisions, which contain the majority of the catecholamine cells in the dorsolateral pons, display a moderate number of immunoreactive fibers. These results are suggestive of interactions between peptide-containing and catecholaminergic neurons and also between-peptide-containing and non-catecholamine-containing neurons in the cat dorsolateral pons.

Neurons containing messenger RNA encoding glutamate decarboxylase in rat hypothalamus demonstrated by in situ hybridization, with special emphasis on cell groups in medial preoptic area, anterior hypothalamic area and dorsomedial hypothalamic nucleus.

Previous deafferentation studies have suggested that most hypothalamic GABAergic innervation originates from neurons within the hypothalamus. We have investigated the distribution of GABAergic cell groups in the rat hypothalamus by means of the in situ hybridization technique, using a cDNA probe for messenger RNA encoding glutamate decarboxylase. Several major GABAergic cell groups were demonstrated, including cells of the tuberomammillary nucleus, arcuate nucleus, suprachiasmatic nucleus, medial preoptic area, anterior hypothalamic area, the dorsomedial hypothalamic nucleus, perifornical area, and lateral hypothalamic area. The most prominent glutamate decarboxylase mRNA-containing cell groups were located in the medial preoptic area, anterior hypothalamic area and dorsomedial hypothalamic nucleus, and were composed of small- to medium-sized neurons. Compared to previously well-characterized GABAergic cell groups in the tuberomammillary nucleus, reticular thalamic nucleus, and non-pyramidal cells of cerebral cortex, the cells of these GABAergic groups demonstrated only weak cDNA labelling, indicating that they contain lower levels of glutamate decarboxylase mRNA. Several types of control experiments supported the specificity of this cDNA labelling, and the GABAergic nature of these cell populations was further supported by detection of glutamate decarboxylase and GABA immunoreactivity. Abundance of GABAergic cells in many hypothalamic nuclei indicates that GABA represents quantitatively the most important transmitter of hypothalamic neurons, and may be involved in neuroendocrine and autonomic regulatory functions.

Catecholaminergic and GABAergic anatomical relationship in the rat substantia nigra, locus coeruleus, and hypothalamic median eminence: immunocytochemical visualization of biosynthetic enzymes on serial semithin plastic-embedded sections.

The visualization of protein antigens has been performed on semithin sections embedded in Araldite. After partial removal of the resin and a light proteolytic treatment of the tissue we were able to localize several biosynthetic enzymes: tyrosine hydroxylase (TH), phenylethanolamine N-methyltransferase (PNMT), and glutamic acid decarboxylase (GAD), which are, respectively, markers of catecholaminergic, adrenergic, gamma-aminobutyric acid (GABA)ergic systems. This technique afforded a high resolution of light microscopy details and immunostaining of TH, GAD, and PNMT on serial sections enabled us to compare with great precision GABAergic and adrenergic innervations in the rat locus coeruleus. In addition, it allows us to study the possible relationship between these terminals and the noradrenergic neurons. We also compared the general pattern of distribution of TH- and GAD-positive endings in the hypothalamic median eminence. The preliminary results obtained with this technique revealed some interesting facts previously unseen when preparations with lower histological resolution were used.

Importance of fixation in immunohistochemistry: use of formaldehyde solutions at variable pH for the localization of tyrosine hydroxylase.

Adequate fixative in immunohistochemistry requires not only a rapid and total immobilization of the antigen, but also a sufficient preservation of its immunoreactivity and maintenance of its accessibility to the immunochemical reagents for localization. Thus, the optimal fixation condition for a specific antigen necessitates a compromise between these opposing variables and can be determined by the preparation of a series of tissues with a progressively increasing degree of fixation. Unless the results of localization using such a series is available, one must be satisfied with adequate but less than optimal results. In the present study, this principle is demonstrated using the localization of tyrosine hydroxylase in the dopaminergic system with formaldehyde as the fixative. The rate and degree of fixation with formaldehyde was shown to be highly pH dependent. By perfusing the tissue with formaldehyde at pH 6.5 (where the rate of fixation is extremely slow) it is possible to rapidly distribute the fixative homogeneously into the tissue. By suddenly changing to a formaldehyde perfusate of higher pH, the cross-linking reaction is rapidly increased. This two-step fixation procedure provides a means of obtaining a rapid and uniform immobilization of the antigen, so that its translocation can be avoided. The final degree of fixation is controlled by the duration and pH of the second fixative solution. The results obtained by increasing the pH of the second solution demonstrated that complete fixation of tyrosine hydroxylase in the dopaminergic system with formaldehyde maybe obtained using a very basic formaldehyde solution (pH 11) while still retaining immunoreactivity of the enzyme. The localization that was achieved at lower pH appeared adequate until it was compared to the results obtained by perfusion at pH 11 in the second step.

Functional status of elderly home care users: do subjects, informal and professional caregivers agree?

Professional or informal proxy respondents are frequently used in surveys when physical or mental health may compromise the ability to participate or the quality of responses. Functional status (Katz activities of daily living [ADL], Lawton instrumental activities of daily living [IADL]) was assessed in a sample of 420 chronically dependent elderly receiving home care. Separate in-person interviews were conducted with subjects, main informal caregivers and professionals coordinating home care. We found substantial agreement (Kappa) particularly between subjects and informal caregivers in all ADL except continence and in all IADL except housekeeping. High levels of agreement were also found for cognitively impaired subjects (Mini-Mental State Examination <24). Disagreement was characterized by more frequent reports of dependence from informal and professional caregivers. Our data suggest that proxy responses by informal caregivers conform with answers provided by subjects but produce slightly higher estimates of dependence and that cognitively impaired elderly living in the community will provide accurate information on their functional status in most cases.

Chronic cocaine increases neurotensin gene expression in the shell of the nucleus accumbens and in discrete regions of the striatum.

The effects of chronic cocaine administration on neurotensin (NT) mRNA expression were investigated in the rat brain using in situ hybridization. Adult Wistar rats were injected daily with cocaine (15 mg/kg i.p.) or saline for 10 days. One hour after the last injection, the brains were removed and coronal sections of the nucleus accumbens and striatum processed for in situ hybridization using a 35S-labeled NT mRNA oligonucleotide probe. Repeated administration of cocaine induced a specific increase in the expression of NT mRNA in the shell of the nucleus accumbens whereas no changes were observed in the core compartment. In addition, cocaine enhanced the expression of the NT gene in neurons confined to the posterior dorsomedial striatum, but did not alter this same region in the anterior striatum. A strong increase in NT mRNA expression was also observed in rats treated with cocaine in the ventrolateral region of the striatum, the fundus striati. No modifications were seen in the dorsolateral or ventromedial striatum, the lateral septum, or the olfactory tubercle. These findings demonstrate that cocaine affects NT mRNA expression in discrete populations of neurons confined to the shell of the nucleus accumbens and dorsomedial and ventrolateral striatum of the rat. The shell of the nucleus accumbens is a limbic area considered the locus of the reinforcing and locomotor activating properties of cocaine while the dorsal striatum is implicated in the regulation of motor output, and appears to be involved in the stereotypies induced by cocaine. The specific increases in NT gene expression induced by chronic cocaine suggest that these changes could be physiologically relevant for the behavioral effects of psychostimulant drugs.

1,25-Dihydroxyvitamin D3 inhibits the expression of inducible nitric oxide synthase in rat central nervous system during experimental allergic encephalomyelitis.

The inducible form of nitric oxide synthase (iNOS) generates nitric oxide of which the excessive production is associated with central nervous system (CNS) inflammatory diseases. The investigation of iNOS expression during experimental allergic encephalomyelitis (EAE) of the Lewis rat demonstrated iNOS immunoreactivity and mRNA both during inflammatory bursts (days 12 and 23 post-immunization) and during the remission phase (day 18). iNOS expression was region-specific and expanded with time along a caudo-rostral axis, thus, correlating with the development of inflammatory infiltrates. Whereas cells of the monocyte/macrophage lineage continuously contributed to iNOS expression, astrocytes only expressed iNOS immunoreactivity or mRNA during the relapse (day 23). In order to investigate possible regulatory effects of 1,25-dihydroxyvitamin D3 (1,25-D3) on iNOS expression, rats were treated with the hormone after the beginning of clinical signs (days 11, 13, 19, 21 and 23 post-immunization), and areas of the CNS were examined at day 23. 1,25-D3 exerted a drastic inhibitory effect on iNOS expression, both at the protein and the mRNA levels. However, this effect was region-specific, and was most pronounced in the cerebellum and brainstem, but non-existent in cerebral cortex. iNOS down-regulation occurred in macrophages, activated microglia and astrocytes. The inhibition of iNOS expression in some CNS structures could account for the improvement of clinical signs observed in EAE-rats treated with 1,25-D3. Since 1,25-D3 can be synthesized by activated macrophages or microglia, our results support the hypothesis that this hormone might be implicated in the control of the CNS-specific immune responses. 1,25-D3 or its analogues could, thus, be of therapeutic value in the management of iNOS-associated diseases of the CNS.