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The lack of translation from basic research into new medicines is a major challenge in CNS drug development. The need to use novel approaches relying on (i) patient clustering based on neurobiology irrespective to symptomatology and (ii) quantitative biomarkers focusing on evolutionarily preserved neurobiological systems allowing back-translation from clinical to nonclinical research has been highlighted. Here we sought to evaluate the mismatch negativity (MMN) response in schizophrenic (SZ) patients, Alzheimer’s disease (AD) patients, and age-matched healthy controls. To evaluate back-translation of the MMN response, we developed EEG-based procedures allowing the measurement of MMN-like responses in a rat model of schizophrenia and a mouse model of AD. Our results indicate a significant MMN attenuation in SZ but not in AD patients. Consistently with the clinical findings, we observed a significant attenuation of deviance detection (~104.7%) in rats subchronically exposed to phencyclidine, while no change was observed in APP/PS1 transgenic mice when compared to wild type. This study provides new insight into the cross-disease evaluation of the MMN response. Our findings suggest further investigations to support the identification of neurobehavioral subtypes that may help patients clustering for precision medicine intervention. Furthermore, we provide evidence that MMN could be used as a quantitative/objective efficacy biomarker during both preclinical and clinical stages of SZ drug development.

Central nervous system diseases are not currently diagnosed based on knowledge of biological mechanisms underlying their symptoms. Greater understanding may be offered through an agnostic approach to traditional disease categories, where learning more about shared biological mechanisms across conditions could potentially reclassify sub-groups of patients to allow realisation of more effective treatments. This review represents the output of the collaborative group “PRISM”, tasked with considering assay choices for assessment of attention and working memory in a transdiagnostic cohort of Alzheimer''s disease and schizophrenia patients exhibiting symptomatic spectra of social withdrawal. A multidimensional analysis of this nature has not been previously attempted. Nominated assays (continuous performance test III, attention network test, digit symbol substitution, N-back, complex span, spatial navigation in a virtual environment) reflected a necessary compromise between the need for broad assessment of the neuropsychological constructs in question with several pragmatic criteria: patient burden, compatibility with neurophysiologic measures and availability of preclinical homologues.

As a part of a comprehensive survey of macroparasites of commercially exploited fish species off the coast of Otago, New Zealand, the parasite fauna of the New Zealand sole Peltorhamphus novaezeelandiae Günther was recently studied. Steringotrema robertpoulini n. sp. is described from this host and compared with known species of Steringotrema Odhner, 1911. The new species is readily distinguished from all of its congeners, except for S. divergens (Rudolphi, 1809) Odhner, 1911, by having the follicular vitellarium divided in four zones rather than two, and can be differentiated from S. divergens mainly by the posterior extent of the intestinal caeca in the hindbody, as well as by host association and geographical distribution. DNA sequences of the 28S ribosomal gene were generated and phylogenetic analyses were undertaken using maximum likelihood and Bayesian inference to assess the phylogenetic position of the new species within the family Fellodistomidae Nicoll, 1909. Analyses included the available sequences for 14 species of the family distributed among eight genera, along with nine species of other members of the order Plagiorchiida La Rue, 1957 as outgroups. The resulting topology shows that the new species of Steringotrema is nested as the sister species of Steringophorus dorsolineatus (Reimer, 1985) Bray, 1995. However, low nodal support indicates that relationships among these species are not fully resolved and require further revision and denser taxon sampling for more detailed molecular work. More information is required to draw further conclusions about the taxonomic status of the genera Steringotrema and Steringophorus Odhner, 1905.

Objectives: Posttraumatic stress disorder (PTSD) is a prevalent, chronic, disabling disorder that may develop following exposure to a traumatic event. This review summarizes currently used animal models of PTSD and their potential role in the development of better therapeutics. Heterogeneity is one of the main characteristics of PTSD with the consequence that many pharmacological approaches are used to relieve symptoms of PTSD. To address the translational properties of the animal models, we discuss the types of stressors used, the rodent correlates of human PTSD (DSM-5) symptoms, and the efficacy of approved, recommended and off-label drugs used to treat PTSD in ‘PTSD-animals’. Conclusions: Currently available animal models reproduce most PTSD symptoms and are validated by existing therapeutics. However, novel therapeutics are needed for this disorder as not one drug alleviates all symptoms and many have side effects that lead to non-compliance among PTSD patients. The true translational power of animal models of PTSD will only be demonstrated when new therapeutics acting through novel mechanisms become available for clinical practice.

Despite the fact that tapeworms comprise the bulk of parasite communities of sharks in marine ecosystems, little is known about their life cycles and, more specifically, about the potential intermediate hosts they utilize as transmission routes. In the absence of morphological features required for specific identification of larval tapeworms from potential intermediate hosts, recent molecular advances have contributed to linking larval and adult parasites and, in some instances, uncovering unknown trophic links. Host–parasite checklists are often the first source of information consulted to assess the diversity and host specificity of parasites, and provide insights into parasite identification. However, these host–parasite checklists are only useful if they encompass the full spectrum of associations between hosts and parasites. A checklist of New Zealand fishes and their parasites has been published, but recent parasitological examinations of commercial fish species reveal that the checklist appears to be far from complete. We focused our current study on a comprehensive survey of macroparasites of a commercial species, the New Zealand sole (Peltorhamphus novaezeelandiae) off the coast of Otago, New Zealand. Specifically, we were expecting to recover marine tapeworms using sharks as their definitive hosts that are generally underreported in parasite surveys. The parasites recovered included tapeworms, flukes, round worms and thorny-headed worms. Surprisingly, a large proportion of the non-tapeworm parasites we recovered were not previously reported from this fish species. A discussion on the potential ecological roles played by this fish species in the transmission of parasites is included.

The processes causing increased hepatic triglycerides (TGs) in mouse models of hepatic steatosis (HS) due to high fat diet (HFD)-induced obesity (DIO), EtOH consumption, or obesity mutations (ob/ob, db/db) are uncertain. This report summarizes two studies. Study 1 focused on regulation by five transcription factors (TFs) (NfKb, Srebp-lc, AMPK, PPARα, PPARγ) of seven, much-studied hepatic long-chain fatty acid (LCFA) transporters (FABPpm, CD36, FATPl, FATP2, FATP4, FATP5, & Caveolin-1 [CAV-1]), and expression of genes for enzymes of LCFA synthesis (SCD-1, FASN) in mice with HS from various causes. Study 2 examined the effects of spexin, a novel adipokine, on obesity, type 2 diabetes mellitus (T2DM), and HS in these mice. Study 1 showed that: (1) processes underlying HS differed in mice with normal leptin signaling (DIO, EtoH-fed) versus those without it (ob/ob, db/db). Increased hepatocellular LCFA uptake was the principal cause of HS in the former, but increased hepatocellular LCFA synthesis predominated in the latter. (2) Expression of individual transporters was variable in the HS models studied, but strong correlations between TF expression and mean expression of four transporter genes across multiple HS models suggested regulatory interaction, and support the postulate that complexes of several different transporters mediate hepatic LCFA uptake. Study 2 indicated (1) that obese DIO mice often also have T2DM and/or nonalcoholic fatty liver disease (NAFLD); (2) confirmed that spexin treatment caused weight loss in DIO mice; (3) in DIO mice with T2DM, spexin also improved glucose tolerance, decreasing insulin resistance and HbAlc. Incubation with spexin directly inhibited LCFA uptake by hepatocytes isolated from DIO mice with HS/NAFLD by ≤70%. Spexin treatment in vivo for 4 weeks reduced hepatic lipids by 60%, and reduced serum alanine and aspartate aminotransferases. These studies in mice with DIO, T2DM, and HS/NAFLD suggest spexin may be an effective treatment for all three conditions.

S 38093, a novel histamine H3 receptor inverse agonist, was tested in a series of neurochemical and behavioral paradigms designed to evaluate its procognitive and arousal properties. In intracerebral microdialysis studies performed in rats, S 38093 dose-dependently increased histamine extracellular levels in the prefrontal cortex and facilitated cholinergic transmission in the prefrontal cortex and hippocampus of rats after acute and chronic administration (10mg/kg i.p.). Acute oral administration of S 38093 at 0.1mg/kg significantly improved spatial working memory in rats in the Morris water maze test. The compound also displayed cognition enhancing properties in the two-trial object recognition task in rats, in a natural forgetting paradigm at 0.3 and 1mg/kg p.o. and in a scopolamine-induced memory deficit situation at 3mg/kg p.o. The property of S 38093 to promote episodic memory was confirmed in a social recognition test in rats at 0.3 and 1mg/kg i.p. Arousal properties of S 38093 were assessed in freely moving rats by using electroencephalographic recordings: at 3 and 10mg/kg i.p., S 38093 significantly reduced slow wave sleep delta power and induced at the highest dose a delay in sleep latency. S 38093 at 10mg/kg p.o. also decreased the barbital-induced sleeping time in rats. Taken together these data indicate that S 38093, a novel H3 inverse agonist, displays cognition enhancing at low doses and arousal properties at higher doses in rodents.

Lactobacillus sakei is a lactic acid bacterium mainly found in meat and meat products. In order to understand the factors favoring its adaptation to meat matrix, growth parameters and survival of the strain L. sakei 23K in the presence of sarcoplasmic or myofibrillar extracts were assessed. Cytosolic proteins putatively involved in the response of this strain to meat proteins were determined using 2D electrophoresis and the significantly regulated proteins were identified by Maldi Tof-MS analyses. From the 31 differentially expressed spots, 16 occurred in the presence of myofibrillar extract while 6 proteins were modulated by the sarcoplasmic extract. Two dipeptidases were overexpressed in the presence of sarcoplasmic proteins, in correlation to the protein degradation patterns obtained by SDS-PAGE. In the presence of the myofibrillar extract, L. sakei 23K overexpressed proteins related to energy and pyrimidine metabolism as well as ala- and tyr-tRNA synthetases, involved in translation, while others corresponding to general stress response, pyrimidine, vitamin and cofactor biosynthesis were down-regulated. The supplementary nutrients furnished by meat extracts modulated the overexpression of proteins related to translation, peptide/amino acid metabolism and energy production while the stress proteins were under regulated. The results obtained here suggest that meat proteins would not represent a stress environment per se for L. sakei 23K in contrast to the harsh conditions during meat processing. This study has extended the understanding of the molecular responses and growth mechanisms of L. sakei 23K in the presence of meat proteins. The transference of genomic information into useful biological insight is an important step for the selection of well-adapted strains for the achievement of high-quality fermented products. Fil: Fadda, Silvina G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Anglade, Patricia. Institut National de la Recherche Agronomique; Francia Fil: Baraige, Fabienne. Institut National de la Recherche Agronomique; Francia Fil: Zagorec, Monique. Institut National de la Recherche Agronomique; Francia Fil: Talon, Régine. Institut National de la Recherche Agronomique; Francia Fil: Vignolo, Graciela Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; Argentina Fil: Champomier Vergès, Marie Christine. Institut National de la Recherche Agronomique; Francia

Nearly one hundred years ago, acetylcholine (ACh) was proposed as a chemical agent responsible for nerve transmission at the synapse, the junction area between one neuron and its target cell. Since it has been proved that ACh played, indeed, a major role in the functioning of the nerve system in the vertebrates, cholinergic nerve transmission became a basic field of study in neuroscience. The birth of histochemistry and its ulterior developments allowed in situ localization of the molecular agents related to the functioning of the cholinergic synapse. This report presents historical landmarks in the histochemistry of major cholinergic agents (acetylcholinesterase, nicotinic acetylcholine receptor, choline acetyltransferase, and ACh), a domain which has greatly contributed to the knowledge of the nerve system. It is emphasized that despite extraordinary progresses made in this field, basic problems, such as in situ localization of ACh, still remain to be solved.

Most antianxiety drugs (anxiolytics) work by modulating neurotransmitters in the brain. Benzodiazepines are fast and effective anxiolytic drugs; however, their long-term use is limited by the development of tolerance and withdrawal symptoms. Ligands of the translocator protein [18 kilodaltons (kD)] may promote the synthesis of endogenous neurosteroids, which also exert anxiolytic effects in animal models. Here, we found that the translocator protein (18 kD) ligand XBD173 enhanced gamma-aminobutyric acid-mediated neurotransmission and counteracted induced panic attacks in rodents in the absence of sedation and tolerance development. XBD173 also exerted antipanic activity in humans and, in contrast to benzodiazepines, did not cause sedation or withdrawal symptoms. Thus, translocator protein (18 kD) ligands are promising candidates for fast-acting anxiolytic drugs with less severe side effects than benzodiazepines.

Analysis of elution profiles of enzymatic and CNBr digests of kappa-caseins C and E, and sequencing of most relevant peptides allowed the chemical characterization of both genetic variants. They differ from their B and A allelic counterparts by a single substitution, His97/Arg and Gly155/Ser, respectively. Electrophoretic behaviour of the investigated C and E variants was in good agreement with the observed amino acid replacements.

International audience; In contrast to other vertebrates, in which the adult brain shows limited adult neurogenesis, teleost fishes exhibit an unparalleled capacity to generate new neurons as adults, suggesting that their brains present a highly permissive environment for the maintenance and proliferation of adult progenitors. Here, we examine the hypothesis that one of the factors permitting establishment of this favourable environment is estradiol. Indeed, recent data showed that radial glial cells strongly expressed one of two aromatase duplicated genes. Aromatase is the estrogen-synthesizing enzyme and this observation is of great interest, given that radial glial cells are progenitor cells capable of generating new neurons. Given the well-documented roles of estrogens on cell fate, and notably on cell proliferation, these data suggest that estradiol could be involved in maintaining and/or activating these progenitors. Examination of recent data in birds and mammals suggests that the situation in fish could well be an exaggeration of a more general mechanism implicating estrogens in neurogenesis. Indeed, there is accumulating evidence that estrogens are involved in embryonic, adult or reparative neurogenesis in other vertebrates, notably in mammals.

The potential memory-enhancing properties of two dopamine agonists currently used in patients with Parkinson's disease, piribedil (1, 10 mg/kg/day, subcutaneously) and bromocriptine (5 mg/kg/day, subcutaneously), were evaluated in three experiments. Although piribedil (10 mg/kg) and bromocriptine equally enhanced spontaneous object recognition in young adult rats (experiment A), only piribedil displayed beneficial effects against aging-related memory impairments in two radial-maze experiments in mice. First (experiment B), a two-stage paradigm of spatial discrimination was used to assess relational/declarative memory in aged mice; piribedil (1 and 10 mg/kg) selectively and significantly improved the performances of aged mice in the critical tests for relational/declarative memory, whereas bromocriptine had no effect. Second, in a novel working memory task (experiment C), vehicle- or bromocriptine-treated aged mice displayed, compared with (vehicle) younger controls, a severe and persistent deficit in short-term retention of successive arm-visits, performing close to chance whichever the retention interval. Performances of piribedil (10 mg/kg) group remarkably improved across testing-days and reached young adults' level. The restoration of specific mnemonic impairments, in aged mice, highlights the memory-enhancing properties of piribedil. The efficacy of this drug in treating cognitive impairment of Parkinson's disease should now be assessed in more specific models.This work was published in an abstract form: ECNP Abstracts, 2005 (P8060 & P8065).

The present study aimed at defining the best scheme of administration of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-positive modulator (S)-2,3-dihydro-[3,4]-cyclopentano-1,2,4-benzothiadiazine-1,1-dioxide (S 18986) [once daily (o.d.) administration of 1 mg/kg for 3 days vs. three times daily (t.i.d.) administration of 0.3 mg/kg for 3 days] to get an optimal procognitive activity in the object recognition task in rats. Memory performance [Recognition Index (RI)] of rats was significantly improved 1 h (RI = 41%, P < 0.01) and 3 h (RI = 46%, P < 0.001) following oral administration of S 18986 (1 mg/kg, o.d.) when compared with animals receiving the vehicle (RI = 6%). When the interval between administration and testing was increased to 6 h and 9 h, no statistically significant improvement in memory performance was observed (RI = 42% for 6 h and RI = 18% for 9 h vs. 20% for the vehicle group). When S 18986 was administered at 0.3 mg/kg t.i.d., no statistically significant improvement in memory performance was observed (RI = 36%). These findings show a long-lasting efficacy of the AMPA receptor allosteric modulator in the object recognition task despite a short half-life in plasma and in brain (approximately 1 h). Accordingly, multiple administrations of S 18986 are not required to obtain a maximal efficacy in this paradigm, because a o.d. schedule of administration leads to a powerful procognitive activity.

To confirm the antidepressant-like activity of agomelatine (S 20098), a melatonin agonist and 5-hydroxytryptamine2C antagonist, already reported in the chronic mild stress and forced swimming tests, the effects of agomelatine were investigated in the learned helplessness test and compared with those of imipramine, melatonin and a selective 5-hydroxytryptamine2C antagonist, SB-242 084. Agomelatine was administered for 5 days either once a day or twice a day, and the effects of pretreatment by a melatonin receptor antagonist, S 22153 (20 mg/kg/day), were studied. A deficit in avoidance learning was observed in helpless control animals. Agomelatine (10 mg/kg/day) administered once a day significantly reduced this deficit with an effect similar to that of imipramine. Effects of agomelatine were abolished by S 22153 pretreatment. Melatonin or SB-242 084 did not reduce the deficit of helpless control animals. These results confirm the antidepressant-like activity of agomelatine and suggest a role of melatonin receptors in its mechanism of action.

Limited clinical data are available on the use of dopamine agonists for the control of motor function and also for the treatment of depression. This study was performed to evaluate the potential effects of the dopamine receptor agonist rotigotine in rat models of anxiety and depression. After repeated administration at doses of 0.05, 0.5, 1, and 5 mg/kg, rotigotine increased spontaneous motor activity at the 5 mg/kg dose after 3-5 days of treatment. At lower doses, the drug had no effect on locomotor activity. After a single administration, rotigotine had no anxiolytic activity in rats during the elevated plus-maze test or the Geller-Seifter conflict test. In the behavioral despair test (also known as the forced swim test), the 5 mg/kg dose of rotigotine enhanced the mobility of rats. Rotigotine (0.5, 1, and 5 mg/kg/day for 5 days) reversed the active avoidance deficit of helpless rats in the learned helplessness test, as shown by a significant decrease in escape failures after 3 to 4 days (0.5 mg/kg/day), 5 days (1 mg/kg/day), and 3 to 5 days (5 mg/kg/day) of treatment. During open-field testing of rats subjected to olfactory bulbectomy and given a 14-day schedule of rotigotine (0.3 mg/kg every 2 days), hyperactivity reversed according to a U-shaped dose-response curve. These results suggest that rotigotine may have antidepressant properties at doses of 1 mg/kg and lower. Potential effects at doses of 5 mg/kg and higher may be masked by an effect of the compound whereby general locomotor activity is enhanced.

Histamine H3 receptor inverse agonists are known to enhance the activity of histaminergic neurons in brain and thereby promote vigilance and cognition. 1-{3-[3-(4-Chlorophenyl)propoxy]propyl}piperidine, hydrochloride (BF2.649) is a novel, potent, and selective nonimidazole inverse agonist at the recombinant human H3 receptor. On the stimulation of guanosine 5'-O-(3-[35S]thio)triphosphate binding to this receptor, BF2.649 behaved as a competitive antagonist with a Ki value of 0.16 nM and as an inverse agonist with an EC50 value of 1.5 nM and an intrinsic activity approximately 50% higher than that of ciproxifan. Its in vitro potency was approximately 6 times lower at the rodent receptor. In mice, the oral bioavailability coefficient, i.e., the ratio of plasma areas under the curve after oral and i.v. administrations, respectively, was 84%. BF2.649 dose dependently enhanced tele-methylhistamine levels in mouse brain, an index of histaminergic neuron activity, with an ED50 value of 1.6 mg/kg p.o., a response that persisted after repeated administrations for 17 days. In rats, the drug enhanced dopamine and acetylcholine levels in microdialysates of the prefrontal cortex. In cats, it markedly enhanced wakefulness at the expense of sleep states and also enhanced fast cortical rhythms of the electroencephalogram, known to be associated with improved vigilance. On the two-trial object recognition test in mice, a promnesiant effect was shown regarding either scopolamine-induced or natural forgetting. These preclinical data suggest that BF2.649 is a valuable drug candidate to be developed in wakefulness or memory deficits and other cognitive disorders.

International audience; Teleost fish are known for exhibiting a high aromatase activity mainly due to the expression of the cyp19b gene, encoding aromatase B (AroB). Recent studies based on both in situ hybridization and immunohistochemistry have demonstrated in three different species that this activity is restricted to radial glial cells. In agreement with measurements of aromatase activity, such aromatase-expressing cells are more abundant in the telencephalon, preoptic area, and mediobasal hypothalamus, although positive cells are also found in the midbrain and hindbrain. Comparative distribution of AroB and estrogen receptor (ERalpha, ERbeta1, and ERbeta2) expression indicates that the preoptic region and hypothalamus are major target for locally produced estradiol (E2) which is likely involved in controlling expression of genes implicated in neuroendocrine regulations. However, AroB and ER have never been reported to be co-expressed in the same cells which is intriguing given that, at least in some species, AroB is strongly up-regulated by E2 itself in agreement with the presence of an estrogen-responsive element (ERE) in the proximal promoter of the cyp19b gene. In vivo data in zebrafish have shown that E2 up-regulates AroB only in radial glial cells. This is in agreement with in vitro transfection experiments indicating that this ERE is functional, but not sufficient, as the E2 regulation of AroB only occurs in glial cell contexts, suggesting a cooperation between ER and so far unidentified glial-specific factors. These data also suggest that radial glial cells may express low amounts of ER that escaped detection until now. The expression of AroB in radial cells, well known for their roles in neurogenesis and now considered as progenitor cells, suggests that local E2 production within these cells could influence the well-documented capacity of the brain of teleosts to grow during adulthood.

The efficacy of antimicrobial agents against pulmonary infections depends on their local concentrations in the lung. The aims of the present study were to: 1) compare technetium-99m diethylenetriaminepenta-acetic acid (99mTc-DTPA) and urea as markers of epithelial lining fluid (ELF) dilution for measuring ELF concentrations of pharmaceuticals; 2) quantify ELF cefepime concentrations in normal and injured lung; and 3) measure the increase in permeability to cefepime following oleic acid-induced acute lung injury. A modified bronchoalveolar lavage technique, based on equilibration of infused 99mTc-DTPA, was used to measure ELF volume. Cefepime was administered intravenously at steady plasma levels. Six serial bronchoalveolar lavages were performed 5 h after the beginning of infusion. ELF to plasma cefepime concentration ratios were 95 +/- 17 and 100 +/- 14.5% in normal and injured lung respectively. When urea was used as marker, cefepime concentration ratios were underestimated at 16.4 +/- 2.7 and 73.9 +/- 8.4% respectively. Cefepime blood/ airspace clearance increased from 3.8 +/- 0.7 micro x min(-1) in controls to 39.8 +/- 4.9 microL x min(-1) in acute lung injury. It was concluded that: 1) cefepime concentrations in epithelial lining fluid were in equilibrium with those in plasma in both normal and injured lung after 5 h at steady plasma concentrations; 2) epithelial lining fluid cefepime concentration by the urea method was much less underestimated in injured versus normal lung; and 3) acute lung injury induces a 10-fold elevation of cefepime blood/airspace clearance.

C57 and DBA mice were trained in a crossed maze to assess possible strain differences in place or response learning as a function of training duration (8 or 17 days) and extramaze cueing conditions. The first condition consisted of a diffuse visually cued environment (rich cueing). The second was the same plus an explicit visual cue marking the direction of the baited arm (rich cueing plus cue). The third was a featureless environment (poor cueing). During training, mice were released from the south arm and rewarded in the east arm. Probe trials on which mice were released from the north arm and allowed to choose either the east (place learning) or the west (response learning) arm were given either on the ninth (PT1) or the eighteenth (PT2) days. Strain x context differences in the activation of the dorsal hippocampus and the dorsolateral striatum were examined by analyzing Fos expression following each probe trial. Results first showed that C57 were essentially place-learners, whereas no learning modality was predominant in DBA, except on the PT2 run with the explicit cue available. Examination of Fos expression in C57 trained under "rich cueing" and "rich cueing plus cue" conditions revealed a strong and parallel increase of immunoreactivity in the hippocampus and dorsolateral striatum following PT1 that decreased under PT2. In that strain, the similar time-course variation of Fos expression in both areas suggests a simultaneous involvement of hippocampal- and striatal-based learning mechanisms, even if those controlled by the hippocampus were prevailing on those controlled by the dorsolateral striatum. In DBA mice, however, the absence of any preferential learning modality was associated with 1) a consistent hippocampal activation persistent across probe trials, and 2) a global superior activation of the dorsolateral striatum. Distinct patterns of Fos expression were therefore associated with every strain-specific learning modality. In each strain, however, each modality was found to be remarkably stable, whatever the training duration and the cueing conditions.

BACKGROUND Total parenteral nutrition (TPN) is used for critically ill patients undergoing surgery, after trauma, or during disease conditions that favor oxidative stress. We studied the effect of TPN on liver oxidative metabolism and antioxidant defenses in rats, and we compared the effect of soybean oil- and olive oil-based diets. METHODS Seven-week-old rats (n = 28) were divided into four groups. Two experimental groups received a TPN solution containing soybean oil (TPN-S) or a mixture of olive/soybean oil, 80/20 (TPN-O), IV for 6 days. Orally fed animals received a solid diet including soybean oil (Oral-S) or olive/soybean oil, 80/20 (Oral-O). The following parameters were measured: DL-alpha-tocopherol, vitamin A, malondialdehyde and thiobarbituric acid reactive substances (MDA-TBARS), and total radical-trapping antioxidant parameter (TRAP) in serum; DL-alpha-tocopherol, vitamin A, glutathione (GSH), and catalase (Cat) activity in liver homogenate; fatty acids from phospholipid, cytochrome P-450 content, NADPH-cytochrome c2 reductase activity in liver microsomes; superoxide dismutase (SOD), glutathione peroxidase (Gpx), glutathione reductase (GR), glutathione transferase (GST), and glucose-6-phosphate dehydrogenase (G6PD) in liver cytosol. RESULTS The soybean or olive oil diets modified the liver microsomal fatty acid phospholipid composition, but the unsaturation index remained unchanged. TPN specifically increased the saturation of the membrane. The cytochrome P-450 level and the NADPH-cytochrome c2 reductase, SOD, Gpx, Cat, and GST activities were unchanged by soybean oil or olive oil diet but decreased receiving TPN. CONCLUSIONS In rats, TPN decreased the liver oxidative metabolism and enzymatic antioxidant defenses. This may be related to saturation of the liver microsomal fatty acids.

LIM/Homeodomain (HD) proteins are classically considered as major transcriptional regulators which, in cooperation with other transcription factors, play critical roles in the developing nervous system. Among LIM/HD proteins, Islet-1 (ISL1) is the earliest known marker of motoneuron differentiation and has been extensively studied in this context. However, ISL1 expression is not restricted to developing motoneurons. In both embryonic and adult central nervous system of rodent and fish, ISL1 is found in discrete brain areas known to express the estrogen receptor (ER). These observations led us to postulate the possible involvement of ISL1 in the control of brain functions by steroid hormones. Dual immunohistochemistry for ISL1 and ER provided evidence for ISL1-ER coexpression by the same neuronal subpopulation within the rat hypothalamic arcuate nucleus. The relationship between ER and ISL1 was further analyzed at the molecular level and we could show that 1) ISL1 directly interacts in vivo and in vitro with the rat ER, as well as with various other nuclear receptors; 2) ISL1-ER interaction is mediated, at least in part, by the ligand binding domain of ER and is significantly strengthened by estradiol; 3) as a consequence, ISL1 prevents ER dimerization in solution, thus leading to a strong and specific inhibition of ER DNA binding activity; 4) ISL1, via its N-terminal LIM domains, specifically inhibits the ER-driven transcriptional activation in some promoter contexts, while ER can serve as a coactivator for ISL1 in other promoter contexts. Taken together, these data suggest that ISL1-ER cross-talk could differentially regulate the expression of ER and ISL1 target genes.

Tetrapod vertebrates express three neuropeptide Y (NPY)-related peptides: NPY, peptide YY (PYY), and pancreatic polypeptide (PP). Both NPY and PYY mRNA have been localized in the brain of tetrapods whereas PP expression is restricted to the pancreas. Some teleost fish commonly produce NPY and PYY but pancreatic peptide Y (PY) instead of PP. Both NPY and PYY mRNAs are widely distributed in the brain of non-tetrapod species, but no information about PY central expression is available. In the present study, molecular riboprobes were used to study PYY and PY mRNA central distribution in the sea bass (Dicentrarchus labrax). PYY and PY gene expression was predominantly detected within the sea bass forebrain. Telencephalic PYY gene expression was restricted to the ventral part of the ventral telencephalon, and no PY expression was detected in the cerebral hemispheres. Both PYY and PY mRNAs were found within the preoptic area and lateral hypothalamus. Distinct PY or PYY mRNA cell groups were localized in the pretectal area and synencephalon or posterior tubercle, respectively. Caudally, PY gene expression was found in the medial reticular formation, whereas PYY transcripts were localized within the vagal lobe. The results demonstrate that vertebrate brain expresses three NPY-related genes and further support the hypothesis that PP and PY arose by independent gene duplications from PYY. The receptor system of the NPY family as well as gene expression within the main hypophysiotropic and feeding behavior areas suggest an involvement of both peptides in the control of food intake and pituitary secretion., We are grateful to Dr. Anglade and Dr. Mazurais for their technical advice. During part of this work J.M.C.-R. was the recipient of a fellowship from the Balaguer-Gonel Foundation. Grant sponsor: CICYT; Grant number: CYTMAR MAR 95-1888-C03-01;Grant sponsor: the Balaguer-Gonel Foundation

The bilateral olfactory bulbectomy resulted in significantly higher plasma concentration of corticosterone, but not of ACTH in basal conditions and much higher plasma ACTH and corticosterone concentrations after 15 min of immobilization stress than were observed in sham-operated animals. Daily treatment with fluoxetine-a specific serotonin reuptake inhibitor-(15 mg/kg/day) had no effect on basal ACTH and corticosterone concentrations in OB rats. Fluoxetine treatment caused lower levels of ACTH, but not of corticosterone secretion, in response to immobilization stress. Bulbectomy significantly reducing 5-HT concentration in the amygdala. Stress increased serotonergic activity in the hypothalamus but not in the amygdala of OB rats. Chronic fluoxetine treatment of both unstressed and stressed OB rats resulted in a lower turnover rate in the two structures. Our results suggest that the hypercorticosteronemia observed after bulbectomy in unstressed OB rats is independent of the serotonergic system in both hypothalamus and amygdala. In contrast, they also demonstrate hypothalamic 5-HT changes in the HPA hyperactivity of OB rats in response to stress. Chronic fluoxetine treatment may normalize pituitary ACTH secretion in response to stress, possibly desensitization of the 5-HT receptors in the hypothalamus due to 5-HT being move available at the synapses.

Drugs and their effects on olfactory learning processes in rats were tested using a modified version of the runway apparatus developed by Ades. Rats were first exposed to a conspecific urine sample and 24 h later were exposed to the same stimulus in the runway. Observations recorded the time spent investigating the urine and the number of sniffs at the site, these being considered to be indices of memory. Diazepam-treated rats (4 or 6 mg/kg) and scopolamine-treated rats (0.5 or 1 mg/kg) showed increases for both parameters. When both drugs were administered simultaneously, the impairing effect was potentiated. However, no changes in learning responses were observed in rats treated with physostigmine (0.125, 0.25, 0.5 mg/kg) or methyl β-carboline-3-carboxylate (0.3, 0.5, 1 mg/kg), although the administration of physostigmine or methyl β-carboline-3-carboxylate was shown to antagonize the impairing effect of diazepam or scopolamine respectively. These observations support the hypothesis of interactions existing between cholinergic agents and benzodiazepine receptor ligands and of such interactions affecting olfactory acquisition processes. The runway apparatus appears to be a valid candidate model to be used for the assessment of pharmacological influences on olfactory learning inrats.

This experiment was designed to assess the role of the septo-hippocampal cholinergic (ACh) system in the deleterious effects produced by systemic benzodiazepine injection on learning processes in rats. Retention of a step through passive avoidance task was analysed after systemic injection of increasing doses of either scopolamine or diazepam applied alone 30 min before the acquisition phase. Results indicated a dose related impairment of retention by each drug: in addition, sub-threshold doses of scopolamine and diazepam applied in combination (diazepam: 2 mg kg plus scopolamine: 0.3 mg kg ) produced a decrease of retention latencies, thus showing an additive effect of the combined treatment. Secondly, a sub-threshold dose of scopolamine ( 15 μg 0.5μl ) was also administered into the medial septal area, together with an i.p. injection of 2mg kg of diazepam. This combined treatment produced a severe impairment of retention, in parallel with a large reduction in emotionality (number of faeces). The data are consistent with the hypothesis that peripheral administration of behaviorally effective doses of diazepam on passive avoidance learning might act partially via a septal ACh-GABA/benzodiazepine mechanism. It is also suggested that this mechanism subserves both anxiety and the memorisation of contextual stimuli associated with passive avoidance acquisition, through the modification of the septo-hippocampal activity.

Removal of the olfactory bulbs results in numerous physiological and behavioral changes in rats. The most frequent and characteristic change is an abnormally high level of corticosterone in the blood, possibly due to changes in the activity of the hypothalamic neurons which synthesize corticotrophin-releasing hormone (CRH). Some of these neurons also synthesize vasopressin (AVP). They are located in the parvocellular part of the paraventricular nucleus of the hypothalamus, which projects into the external layer of the median eminence. We investigated whether there was such a change in activity by studying the synthesis and storage activity of CRH neurons in bulbectomized rats. CRH and AVP axon terminals in frozen sections of the external layer of the median eminence were labeled by immunofluorescence techniques and the degree of labeling was analyzed semi quantitatively. There was no difference in the area or intensity of CRH-labeling in control and bulbectomized rats. However, a significantly larger area was stained for AVP in the bulbectomized than in control rats. We also used in situ hybridization, with single- and double-labeling, to study the effects of bulbectomy on expression of the genes encoding CRH and AVP. No significant difference was found in the levels of mRNA for CRH and the number of CRH+/AVP+ cell bodies was similar in the parvocellular part of the paraventricular nucleus in bulbectomized and normal rats. Our results suggest that the hypothalamo-pituitary-adrenal (HPA) axis changes observed after olfactory bulbectomy may be due to plastic changes in hypothalamic CRH neurons, resulting in greater storage of increased AVP in CRH neurosecretory nerve terminals in the external layer of the median eminence.

The full length cDNA encoding a rainbow trout glucocorticoid receptor (rtGR) has been obtained from rainbow trout liver and intestine libraries. Northern blot analysis showed that the corresponding messengers are detected in the brain of trout with a size 7.5 kb similar to the size of rtGR mRNA in other target tissues. The distribution of the rtGR mRNA and protein was studied in the forebrain of the trout by means of both in situ hybridization and immunohistochemistry and compared with that of the oestrogen receptor (rtER). The GR and ER mRNAs and proteins were detected with a strong overlapping mainly in the: (a) preoptic region; (b) mediobasal hypothalamus; and (c) anterior pituitary, confirming their implication in the neuroendocrine control of pituitary functions. In both diencephalon and pituitary, the peptidergic phenotype of some neuron or cell categories expressing either type of receptors could be determined by double staining. Furthermore, double staining studies have demonstrated colocalization of the two receptors in the same neurons or pituitary cells. The rtER and rtGR were found to be co-expressed in the dopaminergic neurons inhibiting GTH2 secretion and in pituitary cells of the anterior lobe—notably the gonadotrophs. Given that the promoter of the ER gene contains several potential glucocorticoid-responsive elements (GRE) and that cortisol inhibits the oestradiol-stimulated ER expression in the liver, the possibility exists for modulation of ER gene expression by GR in the hypothalamo-pituitary complex. This could explain some of the well documented effects of stress on the reproductive performance in salmonids.

We determine the relative abilities of three bipyridyls (Paraquat P + +, Benzylviologen B + + and Diquat D + +) to stimulate iron-induced lipid peroxidation in relation to their ability to redox cycle and to reduce iron. The ability to redox cycle increases with the redox potential, in the order: P + + < B + + < D + +. The initial rates of Fe3+ reduction increased from P + + to D + + and B + +. NADPH-dependent microsomal lipid peroxidation was measured in different conditions (1) increasing incubation time, 100 microM bipyridyl, 10 microM FeCl3; (2) increasing concentrations of bipyridyls, 10 microM FeCl3, 10 min incubation time; (3) increasing concentrations of FeCl3, 100 microM bipyridyl, 10 min incubation time. Bipyridyls potentiated the production of malondialdehyde (MDA), particularly with the shortest incubation times and the lowest concentrations of FeCl3, in the order of activity P + + < D + + < B + +. The strong correlation between the initial rate of lipid peroxidation and Fe3+ reduction indicates that the rate of Fe3+ reduction determines the intensity of the potentiation effect of bipyridyls on lipid peroxidation--on the condition that the amount of peroxidizable substrate is not the limiting factor.

This study was designed to investigate the pathogenesis of chlorine gas (Cl2) induced acute lung injury and oedema. Isolated blood-perfused rabbit lungs were ventilated either with air (n=7) or air plus 500 parts per million (ppm) of Cl2 (n=7) for 10 min. Capillary pressure, measured by analysing the pressure/time transients of pulmonary arterial, venous and double (both arterial and venous) occlusions, was unchanged in both groups. In Cl2-exposed lungs, the fluid filtration rate increased from -0.228+/-0.25 to 1.823+/-1.23 mL min(-1) x 100 g(-1) (p

Bilateral olfactory bulbectomy (BOX) has major biochemical and behavioral effects, and is one of the most widely investigated of animal models of depression. We studied the consequences of BOX in male rats, on the organization of endogenous circadian rhythms for ACTH, corticosterone (Cort), motor activity (MA) and body temperature (BT). Mean levels were increased for Cort and MA, whereas no significant changes were observed for ACTH and BT. Significantly higher plasma Cort morning values were evidenced in BOX than sham-operated animals. In addition, compared with the single prominent power spectrum for the 24 hours period of control rats, the BOX animals displayed substantially lower 24 hours spectral power for the MA and BT circadian rhythms. These alterations suggest that olfactory bulbectomy, by disruption of the afferences and efferences, induced drastic changes in the function of the endogenous clock or of its regulating systems. From this point of view, bulbectomized rats may therefore be a valuable model to studying the etiology of psychiatric disorders with rhythm disturbance.

Twenty-seven rats were divided into three groups and fed on diets containing 0.3, 6 or 60 RE (retinol equivalent) retinyl palmitate/g food. After 7 weeks, hepatic vitamin A uptake was found to be more efficient in vitamin A-deficient rats than in rats given adequate vitamin A. We showed that during the metabolic adaptation of the animals to the level of vitamin A in the diet, extensive modifications occur in the antioxidant defences of the organism. In parallel with the increase in the level of vitamin A, the decrease in the level of alpha-tocopherol in the plasma can bring about a greater susceptibility of the lipoproteins to oxidative stress. Similarly, the decrease in the hepatic alpha-tocopherol level and in glutathione peroxidase activity leads to the weakening of the liver's antioxidant defences.

The loss of dopaminergic neurons from the substantia nigra in Parkinson's disease (PD) may provoke a reorganization of cellular interactions in the nigrostriatal pathway. Indeed, a plasticity of putative corticostriatal synapses has been evidenced in the striatum of rats with a 6-hydroxy-dopamine-induced lesion of the substantia nigra. However, to our knowledge, synaptic plasticity in the striatum has not previously been investigated in human PD. In this study, we have analysed, at electron microscope level, the morphological characteristics of the synapses formed by afferents in asymmetric contact with dendritic spines of neurons in the caudate nucleus of three patients with PD and three matched controls. The length of the postsynaptic densities and the number of perforated synapses were both significantly increased (24 and 88%, respectively) in the PD patients; the size of these afferents and the surface area occupied by their mitochondria also showed an increase (24 and 50%, respectively), although not statistically significant. The size and density of dendritic spines and the size of postsynaptic density perforations were unchanged. These data indicate the presence of plasticity of the putative corticostriatal synapses in PD and suggest a hyperactivity of cortical afferents to GABAergic neurons.

The capacity of the dopaminergic nerve system to reinnervate the denervated adult striatum was analyzed in a model of partial 6-hydroxydopamine-induced unilateral lesion of rat substantia nigra pars compacta. Sprouting of dopaminergic fibers entering the ventrolateral part of the striatum from a narrow zone of the external capsule was detected on the lesioned side 4 and 7 months, but not 10 days, after lesioning. Ultrastructural examination of the zone of sprouting revealed hypertrophic dopaminergic fibers and growth-cone-like structures, confirming the existence of an ongoing process of spontaneous regrowth of dopaminergic fibers. The identification of the factors involved in the regrowth of dopaminergic fibers may help to orientate molecular research into new treatments for Parkinson's disease.

The main rabbit milk proteins have previously been prepared by reversed-phase HPLC of the acid-precipitated material ('whole casein') and of its supernatant (acid whey). Most of them were nearly homogeneous on SDS-PAGE. Among those isolated from whole casein, alpha s1-, beta- and kappa-caseins, as well as whey acidic protein (WAP) were identified by N-terminal sequencing. After further internal sequencing, two unknown proteins were found to be the putative products, alpha s2a- and alpha s2b-caseins of two recently sequenced transcripts from rabbit mammary gland. Each whole casein component gave several bands on IEF. For kappa-casein, this was probably due to uneven glycosylation as in all kappa-caseins studied so far. For the other whole casein components, including WAP, the number of bands roughly reflected the number of potential phosphorylation sites predicted from the sequences. For alpha s1- and alpha s2-caseins polymorphism could be detected. From acid whey, in addition to WAP, which was a minor component, reversed phase HPLC separated three proteins. These were alpha-lactalbumin, transferrin and serum albumin, on the basis of their apparent molecular weights deduced from SDS-PAGE. WAP was a major component of the native whey obtained by ultracentrifugation of rabbit milk. It was found to consist of two identical subunits linked by at least one disulfide bridge.

Descriptions of the effects of paraquat (P2+) on the peroxidation of liver microsomes are very divergent. Therefore, the presence of ferric iron in the medium and the activity of microsomal mixed-function oxidase system are two factors that we have taken into consideration to explain the discrepancies. The results showed that 100 microM P2+ potentializes the slight production of MDA induced by low concentrations of Fe3+ (or = 15 microM). In these conditions, P+., arising from the one-step reduction of P2+ by NADPH-cytochrome C reductase, could reduce Fe3+ and cause the formation of species that initiate peroxidation. However, unlike the results obtained with CBrCl3, for animals induced by phenobarbital (Ph), the production of MDA in the presence of FeCl3 and of P2+ was weaker than for the controls. The establishment of a new Fe3+/Fe2+ equilibrium owing to increased production of P+. could be responsible.

The regulation of ACTH secretion during stress is a multifactorial process that mainly involves two hypothalamic neurohormones: corticotrophin-releasing factor (CRF) and arginine vasopressin (AVP). In this report we measured, using semiquantitative in situ hybridization, the concentrations of CRF and AVP mRNA in hypophyseotrophic paraventricular parvocellular cell bodies of male rats after an acute (3-h) exposure to insulin-induced hypoglycaemia. Insulin injection (2.5 IU/kg) induced a significant decrease in blood glucose levels and a strong increase in plasma ACTH concentrations. The concentration of CRF mRNA in the paraventricular nucleus (PVN) was significantly increased after insulin-induced hypoglycaemia (150% of control levels), while the number of CRF mRNA-containing cell bodies was not changed. Double-labelling experiments demonstrated that the number of CRF mRNA-containing cell bodies that also contained AVP mRNA was doubled after insulin injection. These data demonstrate that the established increased colocalization of AVP immunoreactivity in nerve terminals immunoreactive for CRF after exposure to stress follows a pretranslational activation of AVP synthesis. Cell-by-cell analysis indicated that the mean CRF hybridization signal was increased in double-labelled cells (about 150% of control levels), suggesting that the increase in CRF gene expression occurs equally in the AVP-synthesizing and in the AVP-deficient CRF mRNA-containing cell bodies. The mean AVP hybridization signal in the double-labelled cells was decreased, suggesting that the amount of AVP mRNA was unchanged in the cell bodies that expressed both CRF and AVP in the basal state and that AVP mRNA levels in the cell bodies recruited after insulin-induced hypoglycaemia were below control values.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzodiazepine (Bzd) agonist, diazepam (Dzp) and inverse agonist methyl beta-carboline-3-carboxylate (beta-CCM); acetylcholinesterase inhibitor, physostigmine (Physo) and muscarinic antagonist, scopolamine (Scopo), were investigated for their mnesic effect in a passive avoidance (PA) task in rats. Impairments were observed after Dzp- and/or Scopo-pretraining treatments. Physo was without effect but antagonized the Dzp-induced impairments. beta-CCM enhanced acquisition and antagonized the Scopo-induced impairing effect. All these drugs had no effect in posttraining administration.

In the neonatal rat, the response of the hypothalamo-pituitary-adrenal axis to stressful stimuli is markedly reduced during the first 2 weeks of life [stress-hyporesponsive period (SHRP)]. In this report, we studied the effect of idazoxan (an alpha 2-adrenergic antagonist) on plasma ACTH and corticosterone levels in 8-day-old rats. Indeed, it is known that in the adult rat, blockade of alpha 2-adrenoceptors increases ACTH secretion stimulated by CRF and arginine vasopressin (AVP) injection. Injection of 2.5 micrograms/g idazoxan induced a rapid (within 30 min) increase in basal plasma ACTH and corticosterone levels that lasted for 60 min. Injection of increasing doses of idazoxan led to a dose-dependent stimulation of ACTH and corticosterone levels. Administration of 2.5 micrograms/g idazoxan significantly increased the ACTH response to insulin-induced hypoglycemia, whereas it potentiated and accelerated the ACTH response to ether exposure stress. We next examined ACTH secretion from superfused anterior pituitary glands. Neither the alpha 2-adrenergic agonist clonidine nor idazoxan changed the basal ACTH secretory rate. Idazoxan had no effect on CRF- and AVP-stimulated ACTH secretion. This indicates that in vivo, idazoxan acts at a suprapituitary level. To investigate a possible effect of idazoxan on presynaptic alpha 2-adrenoceptors, we studied the effect of idazoxan on the concentrations of norepinephrine (NE) and L-DOPA in punches of locus coeruleus after dopa-decarboxylase blockade. Idazoxan injection induced a decrease in the NE content, without changing L-DOPA levels, indicating that idazoxan can act at the level of presynaptic alpha 2-adrenoceptors, inducing an increased release and/or degradation of NE without any effect on catecholamines synthesis. Finally, we investigated a possible involvement of CRF and AVP in mediating the effect of alpha 2-adrenoceptor blockade on ACTH secretion. Passive immunization against CRF or AVP did not change the ACTH response to idazoxan administration, whereas idazoxan pretreatment had simply an additive effect on CRF- and lysine vasopressin-stimulated ACTH secretion. In conclusion, our data demonstrate that during the SHRP, blockade of alpha 2-adrenoceptors induces an increase in both basal and stress-induced ACTH secretion. They suggest that a decreased catecholaminergic tone, consecutive to an increased occupation of alpha 2-adrenoceptors, acting through a central mechanism independent from CRF and AVP may be responsible for the SHRP in the developing rat.

The mechanisms that lead ultimately to neuronal death in pathological ageing of the brain remain mostly unknown as in the case of Parkinson's disease where there is a progressive and selective loss of dopaminergic neurons within the substantia nigra. Dopamine-expressing PC12 cells that were neuronally differentiated by nerve growth factor treatment were chosen as a culture model in which to study some of the changes that may occur during the course of the degenerative process. They were exposed to the calcium ionophore A23187 in order to produce a sustained rise in cytoplasmic calcium, a phenomenon related to various pathological conditions. The degenerative effects of the ionophore were dose- and time-dependent. They were characterized by early fragmentation of the neurites followed ultimately by a loss in cell viability. Biochemical changes, such as a decrease in [3H]dopamine uptake and modulations of the tyrosine hydroxylase gene, were detected before macroscopic evidence of cell suffering (e.g. neurite fragmentation) could be observed. Although an ongoing degenerative process was occurring in cell somata, PC12 cells were able to recover upon ionophore withdrawal. Characteristics of apoptosis such as chromatin condensation and DNA fragmentation were detectable in a small population of dying cells. DNA fragmentation could be prevented by the endonuclease inhibitor aurintricarboxylic acid. New protein synthesis was not required, as cycloheximide failed to prevent degeneration. Taken together, these results suggest that differentiated PC12 cells react to calcium stress through a sequence of regulatory processes which appears to be independent of the apoptotic pathway.

International audience; The brain of adult teleost fish exhibits several unique and interesting features, notably an intense neurogenic activity linked to persistence of radial glial cells acting as neural progenitors, and a high aromatase activity supported by strong expression of the cyp19a1b gene. Strikingly, cyp19a1b expression is restricted to radial glial cells, suggesting that estrogens are able to modulate their activity. This raises the question of the origin, central or peripheral, of C19 androgens available for aromatization. This study aimed to investigate the activity and expression of other main steroidogenic enzymes in the brain of adult zebrafish. We demonstrate by high-performance liquid chromatography that the zebrafish brain has the ability to convert [³H]-pregnenolone into a variety of radiolabeled steroids such as 17OH-pregnenolone, dehydroepiandrosterone, androstenedione, testosterone, dihydro-testosterone, estrone, estradiol, progesterone, and dihydro- and tetrahydro-progesterone. Next, we show by in situ hybridization that messengers for key steroidogenic enzymes, such as Cyp11a1 (P450(SCC)), 3β-Hsd, Cyp17 and Cyp19a1b, are widely expressed in the forebrain where they exhibit an overall similar pattern. By combining aromatase B immunohistochemistry with in situ hybridization, we show that cyp11a1, 3β-hsd and cyp17 messengers are found in part in aromatase B-positive radial processes, suggesting mRNA export. This set of results provides the first demonstration that the brain of fish can produce true neurosteroids, possibly in radial glial cells. Given that radial glial cells are brain stem cells during the entire lifespan of fish, it is suggested that at least some of these neurosteroids are implicated in the persisting neurogenic process.

International audience; In rodents, there is increasing evidence that nuclear progesterone receptors are transiently expressed in many regions of the developing brain, notably outside the hypothalamus. This suggests that progesterone and/or its metabolites could be involved in functions not related to reproduction, particularly in neurodevelopment. In this context, the adult fish brain is of particular interest, as it exhibits constant growth and high neurogenic activity that is supported by radial glia progenitors. However, although synthesis of neuroprogestagens has been documented recently in the brain of zebrafish, information on the presence of progesterone receptors is very limited. In zebrafish, a single nuclear progesterone receptor (pgr) has been cloned and characterized. Here, we demonstrate that this pgr is widely distributed in all regions of the zebrafish brain. Interestingly, we show that Pgr is strongly expressed in radial glial cells and more weakly in neurons. Finally, we present evidence, based on quantitative PCR and immunohistochemistry, that nuclear progesterone receptor mRNA and proteins are upregulated by estrogens in the brain of adult zebrafish. These data document for the first time the finding that radial glial cells are preferential targets for peripheral progestagens and/or neuroprogestagens. Given the crucial roles of radial glial cells in adult neurogenesis, the potential effects of progestagens on their activity and the fate of daughter cells require thorough investigation.

Unlike that of mammals, the brain of adult teleost fish exhibits an intense and widespread neurogenic activity as a result of the persistence of radial glial cells acting as neural progenitors throughout life. Because chemokines, notably CXCL12, and their receptors, such as CXCR4, play key roles in mammalian embryonic neurogenesis, we investigated Cxcr4 and Cxcl12 expressions in the brain of adult zebrafish and their potential relationships with cell proliferation. Cxcr4 expression was found to be restricted to radial glial cells in the adult zebrafish, where it is co-expressed with established radial glial cell markers, such as brain lipid-binding protein (Blbp) or the estrogen-synthesizing enzyme aromatase B (Cyp19a1b). Double stainings combining proliferating cell nuclear antigen (PCNA) and Cxcr4 immunolabelling indicated that there is no obvious association between Cxcr4 expression and radial glial cell proliferation. Interestingly, cxcl12a messengers were detected in ventricular regions, in cells corresponding to aromatase B-immunoreactive radial glial cells. Altogether, our data demonstrate Cxcl12 and Cxcr4 expression in radial glial cells of the brain of adult zebrafish, supporting important roles for the Cxcl12/Cxcr4 pair in brain development and functioning. J. Comp. Neurol. 518:4855–4876, 2010. © 2010 Wiley-Liss, Inc.

The aim of the present study was to evaluate the effects of agomelatine, an antidepressant with melatonergic agonist and 5-HT(2C) antagonist properties, in the rat novel object recognition (NOR) task, a model of short-term episodic memory. To assess the potential involvement of its chronobiotic activity, single intraperitoneal administration of agomelatine and NOR testing were performed either in the evening or in the morning. In both conditions, using a 24h retention interval, vehicle-treated rats did not discriminate between the novel and the familiar object (recognition index was not different from chance performance) while object memory performance of rats treated with agomelatine either in the evening (10 and 40mg/kg) or in the morning (2.5, 10, and 40mg/kg) was significantly improved. Moreover, the selective 5-HT(2C) antagonist SB 242,084 (0.63, 2.5, and 10mg/kg) and melatonin (2.5, 10, and 40mg/kg) displayed also memory facilitating effects in both administration conditions. Finally, thioperamide used as positive reference compound to validate the experimental conditions, demonstrated a memory facilitating effect. In conclusion, agomelatine was shown to possess memory facilitating effects in the rat NOR task and both melatonergic agonist and 5-HT(2C) antagonist properties could be involved in these effects.

International audience; Using genetic monosex male and female rainbow trout populations, the potential sex differences in the central expression of estrogen receptors (esr1, esr2a, esr2b), brain aromatase (cyp19a1b) and some other steroidogenic enzymes was studied over the period of sex differentiation (from 35 to 63 dpf: days post-fertilization) using quantitative polymerase chain reaction (q-PCR). In addition, aromatase activity was evaluated during this period. The results indicated that brain aromatase (cyp19a1b) expression and activity showed a clear and significant sexually dimorphic pattern with higher levels in male brain between 35 and 53 dpf before the time of gonad morphological differentiation. At that time the expression of a key enzyme involved in the conversion of cholesterol into steroids, the cyp11a1 (p450scc), as well as the estrogen receptors were also sexually dimorphic. The dimorphism was lost from 56 dpf onwards. Transcription factors such as nr5a1b (sf1) and nr0b1 (dax1), but not foxl2a were also higher in males than in females. These results demonstrate that, before or during the early period of morphological gonad differentiation, the brain exhibits a clear sexual dimorphism with respect to the expression and activity of aromatase as well as of certain enzymes and factors involved in steroid synthesis as p450scc and sf1. The results suggest a higher potentiality to produce estrogens by male brains during sex differentiation time.

We recently showed that Lactobacillus sakei , a natural meat-borne lactic acid bacterium, can colonize the gastrointestinal tracts (GIT) of axenic mice but that this colonization in the intestinal environment selects L. sakei mutants showing modified colony morphology (small and rough) and cell shape, most probably resulting from the accumulation of various mutations that confer a selective advantage for persistence in the GIT. In the present study, we analyzed such clones, issued from three different L. sakei strains, in order to determine which functions were modified in the mutants. In the elongated filamentous cells of the rough clones, transmission electron microscopy (TEM) analysis showed a septation defect and dotted and slanted black bands, suggesting the presence of a helical structure around the cells. Comparison of the cytoplasmic and cell wall/membrane proteomes of the meat isolate L. sakei 23K and of one of its rough derivatives revealed a modified expression for 38 spots. The expression of six oxidoreductases, several stress proteins, and four ABC transporters was strongly reduced in the GIT-adapted strain, while the actin-like MreB protein responsible for cell shaping was upregulated. In addition, the expression of several enzymes involved in carbohydrate metabolism was modified, which may correlate with the observation of modified growth of mutants on various carbon sources. These results suggest that the modifications leading to a better adaptation to the GIT are pleiotropic and are characterized in a rough mutant by a different stress status, a cell wall modification, and modified use of energy sources, leading to an improved fitness for the colonization of the GIT.

International audience; Unlike that of mammals, the brain of teleost fish exhibits an intense aromatase activity due to the strong expression of one of two aromatase genes (aromatase A or cyp19a1a and aromatase B or cyp19a1b) that arose from a gene duplication event. In situ hybridization, immunohistochemistry and expression of GFP (green fluorescent protein) in transgenic tg(cyp19a1b-GFP) fish demonstrate that aromatase B is only expressed in radial glial cells (RGC) of adult fish. These cells persist throughout life and act as progenitors in the brain of both developing and adult fish. Although aromatase B-positive radial glial cells are most abundant in the preoptic area and the hypothalamus, they are observed throughout the entire central nervous system and spinal cord. In agreement with the fact that brain aromatase activity is correlated to sex steroid levels, the high expression of cyp19a1b is due to an auto-regulatory loop through which estrogens and aromatizable androgens up-regulate aromatase expression. This mechanism involves estrogen receptor binding on an estrogen response element located on the cyp19a1b promoter. Cell specificity is achieved by a mandatory cooperation between estrogen receptors and unidentified glial factors. Given the emerging roles of estrogens in neurogenesis, the unique feature of the adult fish brain suggests that, in addition to classical functions on brain sexual differentiation and sexual behaviour, aromatase expression in radial glial cells could be part of the mechanisms authorizing the maintenance of a high proliferative activity in the brain of fish.

Computerized analysis of video-recorded peristalsis was made in a preparation of guinea-pig ileum tube from which both mucosa and submucosa were mechanically scraped off. Threshold value for provoking peristalsis was higher, conduction velocity of peristalsis was slower, and peristaltic force was weaker in comparison with the ileum tube from which only mucosa was scraped off and with the normal ileum tube. A histological control of the preparation proved that there was no nerve cell body of submucous plexus on the surface of separated circular muscle. It was concluded that peristalsis, though impaired, could be provoked by way of activation of the reflex arch consisted by neural circuit of myenteric neurons which should be produced by excitation of stretch receptors in the muscularis externa.

The zebrafish nuclear progestin receptor (nPR; official symbol PGR) was identified and characterized to better understand its role in regulating reproduction in this well-established teleost model. A full-length cDNA was identified that encoded a 617-amino acid residue protein with high homology to PGRs in other vertebrates, and contained five domains characteristic of nuclear steroid receptors. In contrast to the multiplicity of steroid receptors often found in euteleosts and attributed to probable genome duplication, only a single locus encoding the full-length zebrafish pgr was identified. Cytosolic proteins from pgr-transfected cells showed a high affinity (K(d) = 2 nM), saturable, single-binding site specific for a native progestin in euteleosts, 4-pregnen-17,20 beta-diol-3-one (17,20 beta-DHP). Both 17,20 beta-DHP and progesterone were potent inducers of transcriptional activity in cells transiently transfected with pgr in a dual luciferase reporter assay, whereas androgens and estrogens had little potency. The pgr transcript and protein were abundant in the ovaries, testis, and brain and were scarce or undetectable in the intestine, muscle, and gills. Further analyses indicate that Pgr was expressed robustly in the preoptic region of the hypothalamus in the brain; proliferating spermatogonia and early spermatocytes in the testis; and in follicular cells and early-stage oocytes (stages I and II), with very low levels within maturationally competent late-stage oocytes (IV) in the ovary. The localization of Pgr suggests that it mediates progestin regulation of reproductive signaling in the brain, early germ cell proliferation in testis, and ovarian follicular functions, but not final oocyte or sperm maturation.