Lack of CB1 receptor activity impairs serotonergic negative feedback

Serotonergic and endocannabinoid systems are important substrates for the control of emotional behavior and growing evidence show an involvement in the pathophysiology of mood disorders. In the present study, the absence of the activity of the CB1 cannabinoid receptor impaired serotonergic negative feedback in mice. Thus, in vivo microdialysis experiments revealed increased basal 5-HT extracellular levels and attenuated fluoxetine-induced increase of 5-HT extracellular levels in the prefrontal cortex of CB1 knockout compared to wild-type mice. These observations could be related to the significant reduction in the 5-HT transporter binding site density detected in frontal cortex and hippocampus of CB1 knockout mice. The lack of CB1 receptor also altered some 5-HT receptors related to the 5-HT feedback. Extracellular recordings in the dorsal raphe nucleus revealed that the genetic and pharmacological blockade of CB1 receptor induced a 5-HT1A autoreceptor functional desensitization. In situ hybridization studies showed a reduction in the expression of the 5-HT2C receptor within several brain areas related to the control of the emotional responses, such as the dorsal raphe nucleus, the nucleus accumbens and the paraventricular nucleus of the hypothalamus, whereas an overexpression was observed in the CA3 area of the ventral hippocampus. These results reveal that the lack of CB1 receptor induces a facilitation of the activity of serotonergic neurons in the dorsal raphe nucleus by altering different components of the 5-HT feedback as well as an increase in 5-HT extracellular levels in the prefrontal cortex in mice.

BDNF impairment in the hippocampus is related to enhanced despair behavior in CB1 knockout mice

Stress can cause damage and atrophy of neurons in the hippocampus by deregulating the expression of neurotrophic factors that promote neuronal plasticity. The endocannabinoid system represents a physiological substrate involved in neuroprotection at both cellular and emotional levels. The lack of CB1 receptor alters neuronal plasticity and originates an anxiety-like phenotype in mice. In the present study, CB1 knockout mice exhibited an augmented response to stress revealed by the increased despair behavior and corticosterone levels showed in the tail suspension test and decreased brain derived neurotrophic factor (BDNF) levels in the hippocampus. Interestingly, local administration of BDNF in the hippocampus reversed the increased despair behavior of CB1 knockout mice, confirming the crucial role played by BDNF on the emotional impairment of these mutants. The neurotrophic deficiency seems to be specific for BDNF since no differences were found in the levels of NGF and NT-3, two additional neurotrophic factors. Moreover, BDNF impairment is not related to the activity of its specific receptor TrkB or the activity of the transcription factor CREB. These results suggest that the lack of CB1 receptor originates an enhanced response to stress and neuronal plasticity by decreasing BDNF levels in the hippocampus that lead to impairment in the responses to emotional disturbances.

Hipoglucèmia neonatal en fills de mares que han presentat diabetis gestacional

La hipoglucèmia neonatal (HN) és un problema de salut freqüent en les primeres hores de vida del recent nascut (RN) especialment de mares que pateixen diabetis mellitus (DM) durant l’embaràs, més coneguda com a diabetis gestacional (DG). La diabetis gestacional és un dels principals factors de risc que condiciona a un nadó a presentar hipoglucèmia en les hores posteriors al naixement, per això, els professionals d’infermeria necessiten conèixer la millor manera d’atendre a la dona embarassada que pateix DG amb l’objectiu d’ensenyar-li unes cures personals especifiques per intentar disminuir la incidència de recent nascuts (RN) que presenten hipoglucèmia.

Regulation of GABA(A) and glutamate receptor expression, synaptic facilitation and long-term potentiation in the hippocampus of prion mutant mice

Background: Prionopathies are characterized by spongiform brain degeneration, myoclonia, dementia, and periodic electroencephalographic (EEG) disturbances. The hallmark of prioniopathies is the presence of an abnormal conformational isoform (PrP(sc)) of the natural cellular prion protein (PrP(c)) encoded by the Prnp gene. Although several roles have been attributed to PrP(c), its putative functions in neuronal excitability are unknown. Although early studies of the behavior of Prnp knockout mice described minor changes, later studies report altered behavior. To date, most functional PrP(c) studies on synaptic plasticity have been performed in vitro. To our knowledge, only one electrophysiological study has been performed in vivo in anesthetized mice, by Curtis and coworkers. They reported no significant differences in paired-pulse facilitation or LTP in the CA1 region after Schaffer collateral/commissural pathway stimulation. Principal Findings: Here we explore the role of PrP(c) expression in neurotransmission and neural excitability using wild-type, Prnp -/- and PrP(c)-overexpressing mice (Tg20 strain). By correlating histopathology with electrophysiology in living behaving mice, we demonstrate that both Prnp -/- mice but, more relevantly Tg20 mice show increased susceptibility to KA, leading to significant cell death in the hippocampus. This finding correlates with enhanced synaptic facilitation in paired-pulse experiments and hippocampal LTP in living behaving mutant mice. Gene expression profiling using Illumina microarrays and Ingenuity pathways analysis showed that 129 genes involved in canonical pathways such as Ubiquitination or Neurotransmission were co-regulated in Prnp -/- and Tg20 mice. Lastly, RT-qPCR of neurotransmission-related genes indicated that subunits of GABA(A) and AMPA-kainate receptors are co-regulated in both Prnp -/- and Tg20 mice. Conclusions/Significance: Present results demonstrate that PrP(c) is necessary for the proper homeostatic functioning of hippocampal circuits, because of its relationships with GABA(A) and AMPA-Kainate neurotransmission. New PrP(c) functions have recently been described, which point to PrP(c) as a target for putative therapies in Alzheimer's disease. However, our results indicate that a "gain of function" strategy in Alzheimer's disease, or a "loss of function" in prionopathies, may impair PrP(c) function, with devastating effects. In conclusion, we believe that present data should be taken into account in the development of future therapies.

Reelin controls progenitor cell migration in the healty and pathological adult brain

Understanding the signals that control migration of neural progenitor cells in the adult brain may provide new therapeutic opportunities. Reelin is best known for its role in regulating cell migration during brain development, but we now demonstrate a novel function for reelin in the injured adult brain. First, we show that Reelin is upregulated around lesions. Second, experimentally increasing Reelin expression levels in healthy mouse brain leads to a change in the migratory behavior of subventricular zone-derived progenitors, triggering them to leave the rostral migratory stream (RMS) to which they are normally restricted during their migration to the olfactory bulb. Third, we reveal that Reelin increases endogenous progenitor cell dispersal in periventricular structures independently of any chemoattraction but via cell detachment and chemokinetic action, and thereby potentiates spontaneous cell recruitment to demyelination lesions in the corpus callosum. Conversely, animals lacking Reelin signaling exhibit reduced endogenous progenitor recruitment at the lesion site. Altogether, these results demonstrate that beyond its known role during brain development, Reelin is a key player in post-lesional cell migration in the adult brain. Finally our findings provide proof of concept that allowing progenitors to escape from the RMS is a potential therapeutic approach to promote myelin repair.

Glibenclamide enhances neurogenesis and improves long-term functional recovery after transient focal cerebral ischemia

Glibenclamide is neuroprotective against cerebral ischemia in rats. We studied whether glibenclamide enhances long-term brain repair and improves behavioral recovery after stroke. Adult male Wistar rats were subjected to transient middle cerebral artery occlusion (MCAO) for 90 minutes. A low dose of glibenclamide (total 0.6mg) was administered intravenously 6, 12, and 24 hours after reperfusion. We assessed behavioral outcome during a 30-day follow-up and animals were perfused for histological evaluation. In vitro specific binding of glibenclamide to microglia increased after pro-inflammatory stimuli. In vivo glibenclamide was associated with increased migration of doublecortin-positive cells in the striatum toward the ischemic lesion 72 hours after MCAO, and reactive microglia expressed sulfonylurea receptor 1 (SUR1) and Kir6.2 in the medial striatum. One month after MCAO, glibenclamide was also associated with increased number of NeuN-positive and 5-bromo-2-deoxyuridine-positive neurons in the cortex and hippocampus, and enhanced angiogenesis in the hippocampus. Consequently, glibenclamide-treated MCAO rats showed improved performance in the limb-placing test on postoperative days 22 to 29, and in the cylinder and water-maze test on postoperative day 29. Therefore, acute blockade of SUR1 by glibenclamide enhanced long-term brain repair in MCAO rats, which was associated with improved behavioral outcome.

Effect of maternal clinical chorioamnionitis on neonatal morbidity in very-low birthweight infants: a case control study

Aims: To assess the relationship between maternal clinical chorioamnionitis and neonatal outcome in preterm very-low birthweight (VLBW) infants. Methods: An observational case-control study was conducted in the Neonatology Services of 12 acute-care teaching hospitals in Spain. Between January 2004 and December 2006, all consecutive VLBW (F1500 g) infants born to a mother with clinical chorioamnionitis were enrolled. Controls were infants without chorioamnionitis matched by gestational age who were born immediately after each index case. Results: There were 165 cases and 163 controls. A significantly higher percentage of cases than controls required intubation (53% vs. 35.8%), had normal intrauterine growth (98.1% vs. 84.7%), were born in a tertiary center (inborn) (95.1% vs. 89.1%), from single gestations (76.4% vs. 65.6%) and vaginal delivery (47.3% vs. 33.3%), showed a lowerApgar score at 5 min, and presented a higher rate of earlyonset sepsis (10.4% vs. 1.2%). Older maternal age (32.5 vs. 30.8 years), premature labor (67.3% vs. 25.8%), premature rupture of membranes (61.3% vs. 25.8%), and antibiotic treatment (88.5% vs. 52.3%) were significantly more frequent among cases than controls. Conclusions: After controlling by gestational age, maternal chorioamnionitis was associated with neonatal depression and early sepsis but not with other prematurity-related complications.

Levetiracetam versus Phenobarbital. Effects in the neurodevelopment in newborns treated for neonatal seizures: a clinical trial

Purpose: To analyze if the use of Phenobarbital compared with Levetiracetam, it’s associated with more neurodevelopmental problems in newborns treated for neonatal seizures. As a secondary objective identify which are the most affected areas of the neurodevelopment: cognition, socio-­‐emotional, motor or language skills.Design: A 5 years long clinical trial administering, with double-­‐blind and a randomized distribution of the sample, Phenobarbital or Levetiracetam for the management of neonatal seizures

Effect of maternal clinical chorioamnionitis on neonatal morbidity in very-low birthweight infants: a case control study

Aims: To assess the relationship between maternal clinical chorioamnionitis and neonatal outcome in preterm very-low birthweight (VLBW) infants. Methods: An observational case-control study was conducted in the Neonatology Services of 12 acute-care teaching hospitals in Spain. Between January 2004 and December 2006, all consecutive VLBW (F1500 g) infants born to a mother with clinical chorioamnionitis were enrolled. Controls were infants without chorioamnionitis matched by gestational age who were born immediately after each index case. Results: There were 165 cases and 163 controls. A significantly higher percentage of cases than controls required intubation (53% vs. 35.8%), had normal intrauterine growth (98.1% vs. 84.7%), were born in a tertiary center (inborn) (95.1% vs. 89.1%), from single gestations (76.4% vs. 65.6%) and vaginal delivery (47.3% vs. 33.3%), showed a lowerApgar score at 5 min, and presented a higher rate of earlyonset sepsis (10.4% vs. 1.2%). Older maternal age (32.5 vs. 30.8 years), premature labor (67.3% vs. 25.8%), premature rupture of membranes (61.3% vs. 25.8%), and antibiotic treatment (88.5% vs. 52.3%) were significantly more frequent among cases than controls. Conclusions: After controlling by gestational age, maternal chorioamnionitis was associated with neonatal depression and early sepsis but not with other prematurity-related complications.

Effect of maternal clinical chorioamnionitis on neonatal morbidity in very-low birthweight infants: a case control study

Aims: To assess the relationship between maternal clinical chorioamnionitis and neonatal outcome in preterm very-low birthweight (VLBW) infants. Methods: An observational case-control study was conducted in the Neonatology Services of 12 acute-care teaching hospitals in Spain. Between January 2004 and December 2006, all consecutive VLBW (F1500 g) infants born to a mother with clinical chorioamnionitis were enrolled. Controls were infants without chorioamnionitis matched by gestational age who were born immediately after each index case. Results: There were 165 cases and 163 controls. A significantly higher percentage of cases than controls required intubation (53% vs. 35.8%), had normal intrauterine growth (98.1% vs. 84.7%), were born in a tertiary center (inborn) (95.1% vs. 89.1%), from single gestations (76.4% vs. 65.6%) and vaginal delivery (47.3% vs. 33.3%), showed a lowerApgar score at 5 min, and presented a higher rate of earlyonset sepsis (10.4% vs. 1.2%). Older maternal age (32.5 vs. 30.8 years), premature labor (67.3% vs. 25.8%), premature rupture of membranes (61.3% vs. 25.8%), and antibiotic treatment (88.5% vs. 52.3%) were significantly more frequent among cases than controls. Conclusions: After controlling by gestational age, maternal chorioamnionitis was associated with neonatal depression and early sepsis but not with other prematurity-related complications.

Functional connectivity of reward processing in the brain

Controversial results have been reported concerning the neural mechanisms involved in the processing of rewards and punishments. On the one hand, there is evidence suggesting that monetary gains and losses activate a similar fronto-subcortical network. On the other hand, results of recent studies imply that reward and punishment may engage distinct neural mechanisms. Using functional magnetic resonance imaging (fMRI) we investigated both regional and interregional functional connectivity patterns while participants performed a gambling task featuring unexpectedly high monetary gains and losses. Classical univariate statistical analysis showed that monetary gains and losses activated a similar fronto-striatallimbic network, in which main activation peaks were observed bilaterally in the ventral striatum. Functional connectivity analysis showed similar responses for gain and loss conditions in the insular cortex, the amygdala, and the hippocampus that correlated with the activity observed in the seed region ventral striatum, with the connectivity to the amygdala appearing more pronounced after losses. Larger functional connectivity was found to the medial orbitofrontal cortex for negative outcomes. The fact that different functional patterns were obtained with both analyses suggests that the brain activations observed in the classical univariate approach identifi es the involvement of different functional networks in the current task. These results stress the importance of studying functional connectivity in addition to standard fMRI analysis in reward-related studies.

Glibenclamide enhances neurogenesis and improves long-term functional recovery after transient focal cerebral ischemia

Glibenclamide is neuroprotective against cerebral ischemia in rats. We studied whether glibenclamide enhances long-term brain repair and improves behavioral recovery after stroke. Adult male Wistar rats were subjected to transient middle cerebral artery occlusion (MCAO) for 90 minutes. A low dose of glibenclamide (total 0.6mg) was administered intravenously 6, 12, and 24 hours after reperfusion. We assessed behavioral outcome during a 30-day follow-up and animals were perfused for histological evaluation. In vitro specific binding of glibenclamide to microglia increased after pro-inflammatory stimuli. In vivo glibenclamide was associated with increased migration of doublecortin-positive cells in the striatum toward the ischemic lesion 72 hours after MCAO, and reactive microglia expressed sulfonylurea receptor 1 (SUR1) and Kir6.2 in the medial striatum. One month after MCAO, glibenclamide was also associated with increased number of NeuN-positive and 5-bromo-2-deoxyuridine-positive neurons in the cortex and hippocampus, and enhanced angiogenesis in the hippocampus. Consequently, glibenclamide-treated MCAO rats showed improved performance in the limb-placing test on postoperative days 22 to 29, and in the cylinder and water-maze test on postoperative day 29. Therefore, acute blockade of SUR1 by glibenclamide enhanced long-term brain repair in MCAO rats, which was associated with improved behavioral outcome.

La Detecció universal neonatal de la sordesa a Catalunya : situació actual i reptes de futur

Des de principi dels anys 90, els programes per a la detecció universal neonatal de la sordesa -DUNS- s'han anat implementant arreu del món. La seva aportació a la millora de la competència en llenguatge dels infants sords ha estat forca significativa. A l'Estat espanyol, la DUNS esta possibilitant una detecció molt més precç de la sordesa, cosa que accelera l'establiment del diagnostic i del tractament, i augmenta així les probabilitats que la rehabilitació auditiva dels infants sords sigui reeixida. Des de la perspectiva de l'atenció integral de la sordesa infantil, aquests programes tenen com a objectiu la detecció de la patologia dins el primer mes de vida, el diagnòstic als tres mesos i la instauració del tractament al voltant dels sis mesos. Aquests terminis suposen un autèntic repte que exigeix, d'una banda, la creació de centres qualificats i, de l'altra, la reformulació dels protocols d'actuació dels professionals de les distintes disciplines i la seva adaptació a les noves eines disponibles per al diagnòstic, l'adaptació protètica i la rehabilitació auditiva del nadó sord. Si en un article anterior abordava el futur de la intervenció amb infants sords, tot considerant els avenços tècnics ja existens (Valero, 2002); ara em proposo revisar breument l'estat de la qüestió a Catalunya, alhora que es faran una sèrie de reflexions sobre els canvis que la detecció molt primerenca d'infants sords pot reportar tant per als mateixos sords com per als professionals que els hem d'atendre.

Humeral development from neonatal period to skeletal maturity—application in age and sex assessment

The goal of the present study is to examine cross-sectional information on the growth of the humerus based on the analysis of four measurements, namely, diaphyseal length, transversal diameter of the proximal (metaphyseal) end of the shaft, epicondylar breadth and vertical diameter of the head. This analysis was performed in 181 individuals (90 ♂ and 91 ♀) ranging from birth to 25 years of age and belonging to three documented Western European skeletal collections (Coimbra, Lisbon and St. Bride). After testing the homogeneity of the sample, the existence of sexual differences (Student"s t- and Mann-Whitney U-test) and the growth of the variables (polynomial regression) were evaluated. The results showed the presence of sexual differences in epicondylar breadth above 20 years of age and vertical diameter of the head from 15 years of age, thus indicating that these two variables may be of use in determining sex from that age onward. The growth pattern of the variables showed a continuous increase and followed first- and second-degree polynomials. However, growth of the transversal diameter of the proximal end of the shaft followed a fourth-degree polynomial. Strong correlation coefficients were identified between humeral size and age for each of the four metric variables. These results indicate that any of the humeral measurements studied herein is likely to serve as a useful means of estimating sub-adult age in forensic samples.

3,4-Methylenedioxy-methamphetamine induces in vivo regional up-regulation of central nicotinic receptors in rats and potentiates the regulatory effects of nicotine on these receptors

Nicotine (NIC), the main psychostimulant compound of smoked tobacco, exerts its effects through activation of central nicotinic acetylcholine receptors (nAChR), which become up-regulated after chronic administration. Recent work has demonstrated that the recreational drug 3,4-methylenedioxymethamphetamine (MDMA) has affinity for nAChR and also induces up-regulation of nAChR in PC 12 cells. Tobacco and MDMA are often consumed together. In the present work we studied the in vivo effect of a classic chronic dosing schedule of MDMA in rats, alone or combined with a chronic schedule of NIC, on the density of nAChR and on serotonin reuptake transporters. MDMA induced significant decreases in [3H]paroxetine binding in the cortex and hippocampus measured 24 h after the last dose and these decreases were not modified by the association with NIC. In the prefrontal cortex, NIC and MDMA each induced significant increases in [3H]epibatidine binding (29.5 and 34.6%, respectively) with respect to saline-treated rats, and these increases were significantly potentiated (up to 72.1%) when the two drugs were associated. Also in this area, [3H]methyllycaconitine binding was increased a 42.1% with NIC + MDMA but not when they were given alone. In the hippocampus, MDMA potentiated the a7 regulatory effects of NIC (raising a 25.5% increase to 52.5%) but alone was devoid of effect. MDMA had no effect on heteromeric nAChR in striatum and a coronal section of the midbrain containing superior colliculi, geniculate nuclei, substantia nigra and ventral tegmental area. Specific immunoprecipitation of solubilised receptors suggests that the up-regulated heteromeric nAChRs contain a4 and b2 subunits. Western blots with specific a4 and a7 antibodies showed no significant differences between the groups, indicating that, as reported for nicotine, up-regulation caused by MDMA is due to post-translational events rather than increased receptor synthesis.