bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphatidylinositol 3‐kinase inhibition enhances human sperm motility and sperm–zona pellucida binding
Authors: Du Plessis S. S. , Franken D. R. , Baldi E. , Luconi M. 
Published: December 2004

SummaryVarious signalling pathways are involved in the regulation of sperm motility, capacitation, acrosome reaction and sperm–zona binding. Recent data pointed out an important role for phosphatidylinositol 3‐kinase (PI3K) in human sperm motility. However, no study as of yet has been carried out to determine the effect of sperm treatment with the PI3K inhibitor LY294002 on other sperm parameters. In the present study, we investigated the role of PI3K on human sperm motility, acrosome reaction and sperm–oocyte binding by using this inhibitor. We demonstrate that in vitro incubation of washed unselected spermatozoa with LY294002 increased the percentage motility and progressive motility in asthenozoospermia patients as evaluated by computer‐aided sperm analysis. The compound furthermore did not influence the acrosome reaction, whilst it (further) slightly enhanced sperm‐oocyte binding. Our results therefore imply that PI3K negatively affects sperm motility and oocyte binding and might suggest a possible therapeutic role for PI3K inhibitors in the treatment regime for asthenozoospermia.
A Test of the Cross‐Generational Transmission of Grooming Preferences in Macaques
Authors: Schino Gabriele , Aureli Filippo , Ventura Raffaella , Troisi Alfonso 
Published: December 2004

AbstractIn this study we compared the grooming networks of macaque mothers and adult daughters in order to test whether primate social preferences may be transmitted from one generation to the next. We studied four social groups belonging to three different species (Macaca fascicularis, M. fuscata and M. sylvanus). We found no evidence for the transmission of individual degrees of kin bias or of preference for high‐ranking individuals (transmission of ‘rules of choice’). Only in one of four social groups were idiosyncratic interindividual preferences of mothers significantly similar to those of their adult daughters. Overall, the results of this study question the generality of the intergenerational transmission of social preferences in macaques. It is suggested that species‐specific degrees of preferences for kin and for high‐ranking individuals should be selected for and strategically adjusted by individual females in relation to social circumstances.
Evidence for a GABAergic projection from the central nucleus of the amygdala to the brainstem of the macaque monkey: a combined retrograde tracing andin situhybridization study
Authors: Jongen‐Rêlo Ana L. , Amaral David G. 
Published: December 2004

AbstractThe central nucleus of the amygdala is interconnected with a variety of visceral and autonomic nuclei of the brainstem. These include the parabrachial nucleus, the nucleus of the solitary tract, the nucleus ambiguus and the dorsal motor nucleus of the vagus. Despite repeated attempts, neurochemical characterization of the major subcortical connections of the central nucleus has not yet been accomplished. Based on earlier immunohistochemical andin situhybridization evidence indicating the presence of numerous GABAergic neurons in the macaque monkey central nucleus, we predicted that a sizeable portion of the descending projections may be GABAergic. We tested this hypothesis using a novel double labelling method with gold conjugated WGA‐apoHRP as a retrograde tracer andin situhybridization for detecting the mRNA that encodes the enzyme glutamic acid decarboxylase (GAD67) as a marker for GABAergic cells. Following WGA‐apoHRP‐gold injections into the brainstem, a large number of retrogradely labelled cells was observed in the medial and lateral divisions of the central nucleus. Of the retrogradely labelled cells observed in the medial division of the central nucleus, approximately half were double‐labelled for GAD67 mRNA; about 30% double labelling was observed in the lateral division. These data support the view that a sizeable component of the central nucleus projection to the brainstem is GABAergic.
Neurotrophin‐3 promotes cerebellar granule cell exit from the EGL
Authors: Doughty Martin L. , Lohof Ann , Campana Aline , Delhaye‐Bouchaud Nicole , Mariani Jean 
Published: December 2004

AbstractIn the cerebellum, the mRNAs for neurotrophin‐3 (NT‐3) and its high‐affinity tyrosine kinase receptor trkC are expressed by both the differentiated granule cells of the internal granule cell layer (IGL) and their precursors in the external germinal layer (EGL). We have investigated the effects of chronic application of exogenous NT‐3 in vivo on cerebellar granule cell genesis and differentiation. NT‐3 was applied to the posterior surface of the rat cerebellum from P6 onwards using Elvax implants. At P10 the EGL of cerebellar lobules VII and VIII was significantly reduced in thickness in NT‐3 implanted rats when compared with controls. Immunocytochemical analysis of the EGL using antibodies to proliferating cell nuclear antigen (PCNA) revealed that the number of postmitotic, premigratory (PCNA‐immunonegative) granule cell precursors was preferentially reduced in the NT‐3 implanted rats. In situ DNA fragmentation labelling confirmed that this was not accompanied by increased cell death in the EGL. These results suggest that NT‐3 promotes the differentiation of postmitotic, premigratory granule cell precursors, accelerating cell exit from the EGL.
Calretinin expression as a critical component in the control of dentate gyrus long‐term potentiation induction in mice
Authors: Gurden Hirac , Schiffmann Serge N. , Lemaire Martine , Böhme Georg A. , Parmentier Marc , Schurmans Stéphane 
Published: December 2004

AbstractWe have recently reported that mice homozygous (Cr–/–) for a null mutation in the calretinin gene have impaired long‐term potentiation (LTP) induction in the dentate gyrus (S. Schurmans et al. (1997) Proc. Natl. Acad. Sci. USA, 94, 10415). Here, we investigated dentate LTP induction in mice heterozygous (Cr+/–) for the same mutation. Despite the presence of calretinin in neurons of these mice, although at reduced levels as compared with normal mice, LTP induction in dentate gyrus was totally impaired. Spatial memory and learning were found unaffected in Cr+/– mice, such as in Cr–/– mice. Altogether, our results suggest that calretinin is a critical component in the control of dentate synaptic plasticity in mice, and that levels of calretinin higher than those observed in Cr+/– mice are required to induce LTP in this area. The possible mechanisms leading to the absence of correlation between gene dosage and biological effects are discussed.
Contextual fear conditioning regulates the expression of brain‐specific small nucleolar RNAs in hippocampus
Authors: Rogelj Boris , Hartmann Christoph E. A. , Yeo Christopher H. , Hunt Stephen P. , Giese K. Peter 
Published: December 2004

AbstractSome small nucleolar RNAs (snoRNAs) are exclusively expressed in the brain but they have no known role in higher brain function. We analysed the expression pattern of four brain‐specific snoRNAs: MBI‐36, MBII‐48, MBII‐52 and MBII‐85, in mouse brain using in situ hybridization. All of these genes were expressed in the hippocampus and, except for MBII‐85, their levels in ventral parts were higher than those in dorsal parts. Using quantitative real‐time polymer chain reaction we determined hippocampal expression changes after contextual fear conditioning in mice. Ninety minutes, but not 25 h, after conditioning, we observed significant downregulation of MBII‐48 and upregulation of MBII‐52. Our finding that the expression of MBII‐48 and MBII‐52 is regulated during learning suggests that these snoRNAs have an important role in higher brain function.
Glutamatergic modulation of synaptic plasticity at a PNS vertebrate cholinergic synapse
Authors: Pinard Audrée , Lévesque Sébastien , Vallée Joanne , Robitaille Richard 
Published: December 2004

AbstractThe presence and the functionality of a glutamatergic regulation was studied at the frog neuromuscular junction (NMJ), a singly innervated cholinergic synapse. Bath application of glutamate reduced transmitter release without affecting nerve‐evoked presynaptic Ca2+ entry and handling. (1S,3R)‐aminocyclopentanedicarboxylic acid (ACPD), a metabotropic glutamate receptor (mGluR) agonist, mimicked the effects of glutamate while (S)‐alpha‐methyl‐4‐carboxyphenylglycine (MCPG), a mGluR antagonist, blocked glutamate effects. MCPG had no effect on transmitter release evoked at low frequency (0.2 Hz) but significantly reduced synaptic depression (10 Hz, 80 s). This suggests that a frequency‐dependent endogenous glutamatergic modulation is present at the frog NMJ and is mediated through mGluRs. Immunohistochemical labelling revealed the presence of mGluRs at the end plate area, primarily on muscle fibers. Functional glutamate uptake machinery was also found at the NMJ as blockade of glutamate transport by the inhibitor dl‐threo‐β‐benzyloxyaspartate (DL‐TBOA) increased high frequency‐induced depression, suggesting that the transporters system is used to eliminate glutamate from the extracellular space. Moreover, immunohistochemical labelling revealed that glutamate‐aspartate transporters (GLASTs) are predominantly present on perisynaptic Schwann cells (PSCs). However, local application of glutamate on PSCs unreliability evoked small Ca2+ responses. Hence, these data suggest that functional glutamatergic interactions at a purely cholinergic synapse, shape synaptic efficacy and short‐term plasticity in a frequency‐dependent fashion.
Functional heterogeneity of the responses of histaminergic neuron subpopulations to various stress challenges
Authors: Miklós I. H. , Kovács K. J. 
Published: December 2004

AbstractIn rats, the cell bodies of the histaminergic neuronal system are clustered in five distinct cell groups (E1–E5) within the posterior hypothalamus. On the basis of tract tracing studies, these histaminergic subgroups have been regarded as one functional unit. In addition to its well‐characterized role in arousal, locomotor activity, metabolism, feeding, drinking and behaviour, as well as in coordination of autonomic functions, histamine has been implicated in regulation of the hypothalamo–pituitary–adrenocortical axis during stress. To address the capacity of different histaminergic subgroups to respond to various challenges, we revealed c‐Fos, the immediate early gene marker of activated neurons, in histamine synthesizing neurons by combining c‐Fos immunocytochemistry with in situ hybridization of histidine decarboxylase (HDC) mRNA. Compared to the negligible colocalization of these markers in control rats, restraint, insulin‐induced hypoglycaemia and foot shock resulted in specific activation of histamine synthesizing neurons of the E4 and E5 subgroup in the tuberomammillary region. Up to 36% of HDC mRNA‐expressing cells show c‐Fos immunoreactivity in the E5 region. In addition, some neurons of the E1, E2 and E3 histaminergic groups were activated after restraint stress. Many less c‐Fos‐positive histaminergic neurons were detected after immobilization and dehydration. Ether stress, acute hyperosmotic stimulus or injection of bacterial lipopolysaccharide did not activate hypothalamic HDC‐positive neurons. These results suggest, for the first time, the functional heterogeneity of histaminergic neuron population, the components of which are recruited in a stressor‐ and subgroup‐specific manner.
Structural and functional dichotomy of human midcingulate cortex
Authors: Vogt Brent A. , Berger Gail R. , Derbyshire Stuart W. G. 
Published: December 2004

AbstractAnterior cingulate cortex is comprised of perigenual and midcingulate regions based on cytology, imaging and connections. Its anterior (aMCC) and posterior (pMCC) parts and transition to posterior area 23 were evaluated in six human cingulate gyri with Nissl staining and immunoreactions for neuron‐specific nuclear binding protein and intermediate neurofilament proteins (NFP), and their pain and emotion functions evaluated in standard coordinates. Morphological differences included a poorly differentiated layer III with few NFP‐expressing neurons in aMCC and a very dense layer Va with small and large pyramids intermingled in pMCC. The density of NFP‐positive, layer Vb neurons was higher in pMCC than in aMCC. The junction of pMCC with area 23 had a dysgranular area 23d with clumps of layer IV neurons and a very dense layer Va. Each case was co‐registered to standard coordinates and the regional borders identified and measured. Although both regions had overall equivalent activations during noxious cutaneous thermal stimulation, the posterior two‐thirds of pMCC was relatively inactive. About 60% of fear‐induced activity was in aMCC, sadness and happiness activated perigenual cortex, and neither were activated with non‐emotion tasks. Thus, pain activity is coupled to fear in aMCC, while other MCC processing is not related to affect. Beyond midcingulate duality, this is the first report of a very dense layer Va for areas p24′ and 23 and the features of transitional area 23d. The MCC dichotomy suggests that two circuits differentially regulate the two cingulate motor areas, and involvement of aMCC in pain and fear make it selectively vulnerable to chronic pain and stress syndromes.
Implication of corticosteroid receptors in the regulation of hippocampal structural plasticity
Authors: Montaron M. F. , Piazza P. V. , Aurousseau C. , Urani A. , Le Moal M. , Abrous D. N. 
Published: December 2004

AbstractThe dentate gyrus is one of the few areas of the adult brain that continues to produce neurons and to express the embryonic polysialylated isoforms of neuronal cell adhesion molecules (PSA‐NCAM). The stress hormone corticosterone exerts a complex modulation on neurogenesis and PSA‐NCAM, and previous studies have shown that mature granule cells require corticosterone for their survival. Thus, the aim of our work was to investigate the respective role of the different corticosteroid receptors on these three parameters in adrenalectomized rats. It was found that treatment with a low dose of the mineralocorticoid receptor agonist, aldosterone, prevents only the adrenalectomy‐induced increase in cell death. Treatment with a higher dose of aldosterone normalized cell proliferation whereas PSA‐NCAM expression was normalized only by treatment with the glucocorticoid receptor agonist, RU 28362. It is concluded that stimulation of the mineralocorticoid receptor is sufficient to mediate the effects of corticosterone on neurogenesis and to protect mature cells from cell death whereas stimulation of the glucocorticoid receptor is necessary to modulate PSA‐NCAM expression.
Light‐induced c‐fos in melanopsin retinal ganglion cells of young and aged rodless/coneless (rd/rd cl) mice
Authors: Semo Ma'ayan , Lupi Daniela , Peirson Stuart N. , Butler Jason N. , Foster Russell G. 
Published: December 2004

AbstractNon‐rod, non‐cone ocular photoreceptors have been shown to mediate a range of irradiance detection tasks. The strongest candidates for these receptors are melanopsin‐positive retinal ganglion cells (RGCs). To provide a more complete understanding of these receptors in vivo, we have utilized a mouse that lacks rod and cone photoreceptors (rd/rd cl) and compared these animals to congenic wild‐types. Using real‐time polymerase chain reaction and immunohistochemistry, we address the following. (1) Is Fos expression within these RGCs driven by an input from the rods/cones or is it the product of the intrinsic photosensitivity of these neurons? We demonstrate that most Fos expression across the entire retina is due to the rods/cones, but in the absence of these photoreceptors, light will induce Fos within melanopsin RGCs. (2) Could the reported age‐related decline in circadian photosensitivity of rodents be linked to changes in the population of melanopsin RGCs? We show that old mice experience an ∼ 40% reduction in melanopsin RGCs. (3) Does the loss of inner retinal neurons affect the responses of melanopsin RGCs? Aged (∼ 700 days) rd/rd cl mice lose most of their inner retina but retain the retinal ganglion cell layer. In these mice, the proportion of melanopsin RGCs that express Fos in response to light is significantly reduced. Collectively, our data suggest that melanopsin RGCs form a heterogeneous population of neurons, and that most of the light‐induced c‐fos expression within these cells is associated with the endogenous photosensitivity of these neurons.
Developmental up‐regulation of KCC2 in the absence of GABAergic and glutamatergic transmission
Authors: Ludwig Anastasia , Li Hong , Saarma Mart , Kaila Kai , Rivera Claudio 
Published: December 2004

AbstractPostsynaptic γ‐aminobutyric acid (GABA)A‐mediated responses switch from depolarizing to hyperpolarizing during postnatal development of the rodent hippocampus. This is attributable to a decrease in the concentration of intracellular chloride set by the expression of the neuron‐specific K+‐Cl− co‐transporter, KCC2. A recent in vitro study [Ganguly et al. (2001) Cell, 105, 521–532] showed that KCC2 expression may be under the trophic control of GABAA receptor‐mediated transmission. Here we have studied the developmental expression of KCC2 protein in mouse hippocampal dissociated cultures as well as organotypic cultures. A low somatic expression level was found in neurons prior to the formation of the first synapses, as detected by synaptophysin immunoreactivity. Thereafter, KCC2 expression was strongly up‐regulated during neuronal maturation. The developmental up‐regulation of KCC2 expression was not altered by a chronic application (throughout the culturing period; 2–15 days in vitro) of the action‐potential blocker TTX or the N‐methyl‐d‐aspartate (NMDA) and non‐NMDA antagonists APV and NBQX. Blockade of GABAA‐mediated transmission with picrotoxin did not affect the expression levels of KCC2 protein either. These data show that neither neuronal spiking nor ionotropic glutamatergic and GABAergic transmission are required for the developmental expression of KCC2 in mouse hippocampal neurons in vitro.
Central representation of bladder and colon revealed by dual transsynaptic tracing in the rat: substrates for pelvic visceral coordination
Authors: Rouzade‐Dominguez Marie‐Laure , Miselis Richard , Valentino Rita J. 
Published: December 2004

AbstractThe neurocircuitry underlying regulation of bladder and distal colon function by Barrington's nucleus (the pontine micturition centre) was investigated in rats by identifying neurons which were transsynaptically labelled from these viscera, with pseudorabies virus (PRV) or genetically modified forms of PRV [PRV–β‐galactosidase (PRV‐β‐Gal) and PRV–green fluorescent protein (PRV‐GFP)]. PRV injection into the bladder or the colon of separate rats suggested an overlap in the distribution of bladder‐ and colon‐related neurons in Barrington's nucleus, as well as a topographical arrangement whereby dorsal neurons were bladder‐related and ventral neurons were colon‐related. In rats injected with PRV‐β‐Gal into one viscera and PRV‐GFP into another, neurons in the major pelvic ganglion and lumbosacral spinal cord were primarily single‐labelled at relatively early survival times. With longer survival times many double‐labelled neurons (>70%) appeared in Barrington's nucleus, suggesting that individual Barrington's nucleus neurons are synaptically linked to preganglionic parasympathetic neurons which independently innervate the colon or the bladder. In addition to these dual‐labelled neurons, Barrington's nucleus neurons which were single‐labelled from either viscera were observed and these exhibited a viscerotopic organization consistent with the single‐labelling studies. Together, these findings suggest the existence of three neuronal populations in Barrington's nucleus, one which is synaptically linked to both the bladder and the colon and the other two populations which are specifically linked to either viscera. These anatomical substrates may underlie the central coordination of bladder and colon function and play a role in disorders characterized by a coexistence of bladder and colonic symptoms.
Disruption of prepulse inhibition in mice lacking mGluR1
Authors: Brody S. A. , Conquet F. , Geyer M. A. 
Published: December 2004

AbstractSensorimotor gating, measured by prepulse inhibition of the startle response (PPI), is a cross‐species form of information processing that is deficient in patients with schizophrenia and is widely used as a model to study the neurobiology of this disorder. The eight known metabotropic glutamate receptors (mGluRs) are divided into three groups on the basis of sequence homology and pharmacological properties. Group I consists of mGluR5 and mGluR1, both of which are coupled positively to phospholipase C. Mice lacking mGluR5 exhibit a deficit in PPI. Like mGluR5, mGluR1 is located in regions that are involved in the modulation of PPI. To test the hypothesis that mGluR1 is involved in the modulation of PPI we assessed PPI in mGluR1 knockout (KO) mice. Littermate mGluR1 wild‐type and KO mice were tested at multiple ages in a standard PPI paradigm containing a 65 dB background, 120 dB pulses and prepulses of 69, 73 and 77 dB. At all ages tested, mGluR1 KO mice exhibited a significant PPI deficit. The PPI deficit of the mGluR1 KO mice was not further exaggerated by administration of the N‐methyl‐d‐aspartate antagonist phencyclidine nor was it reversed by administration of the dopamine antagonist raclopride (3.0 mg/kg). The PPI deficit of the mGluR1 KO mice was, however, ameliorated by administration of the mood stabilizer lamotrigine (27 mg/kg base equivalent weight), though increases in PPI were also seen with lamotrigine in the wild‐type mice. Thus, both group I metabotropic glutamate receptors are involved in the regulation of PPI in mice.
The subcellular localization of GABAB receptor subunits in the rat substantia nigra
Authors: Boyes Justin , Bolam J. Paul 
Published: December 2004

AbstractThe inhibitory effects of GABA within the substantia nigra (SN) are mediated in part by metabotropic GABAB receptors. To better understand the mechanisms underlying these effects, we have examined the subcellular localization of the GABAB receptor subunits, GABAB1 and GABAB2, in SN neurons and afferents using pre‐embedding immunocytochemistry combined with anterograde or retrograde labelling. In both the SN pars compacta (SNc) and pars reticulata (SNr), GABAB1 and GABAB2 showed overlapping, but distinct, patterns of immunolabelling. GABAB1 was more strongly expressed by putative dopaminergic neurons in the SNc than by SNr projection neurons, whereas GABAB2 was mainly expressed in the neuropil of both regions. Immunogold labelling for GABAB1 and GABAB2 was localized in presynaptic and postsynaptic elements throughout the SN. The majority of labelling was intracellular or was associated with extrasynaptic sites on the plasma membrane. In addition, labelling for both subunits was found on the presynaptic and postsynaptic membranes at symmetric, putative GABAergic synapses, including those formed by anterogradely labelled striatonigral and pallidonigral terminals. Labelling was also observed on the presynaptic membrane and at the edge of the postsynaptic density at asymmetric, putative excitatory synapses. Double immunolabelling, using the vesicular glutamate transporter 2, revealed the glutamatergic nature of many of the immunogold‐labelled asymmetric synapses. The widespread distribution of GABAB subunits in the SNc and SNr suggests that GABAB‐mediated effects in these regions are likely to be more complex than previously described, involving presynaptic autoreceptors and heteroreceptors, and postsynaptic receptors on different populations of SN neurons.