Foreground contextual fear memory consolidation requires two independent phases of hippocampal ERK/CREB activation.

Fear conditioning is a popular model for investigating physiological and cellular mechanisms of memory formation. In this paradigm, a footshock is either systematically associated to a tone (paired conditioning) or is pseudorandomly distributed (unpaired conditioning). In the former procedure, the tone/shock association is acquired, whereas in the latter procedure, the context/shock association will prevail.

Reinforcing effects of nicotine microinjections into the ventral tegmental area of mice: dependence on cholinergic nicotinic and dopaminergic D1 receptors.

We used an intracranial self-administration (ICSA) procedure to assess the involvement of the ventral tegmental area (VTA) nicotinic receptors in the rewarding effects of nicotine. We then challenged intra-VTA nicotine self-administration via systemic or local injections of dopamine (DA)-D1 and nicotinic receptor antagonists. C57BL/6J mice were stereotaxically implanted unilaterally with a guide cannula above the VTA.

Both arginine and fructose stimulate pH-independent resistance in the wine bacteria Oenococcus oeni.

The wine bacteria Oenococcus oeni has to cope with harsh environmental conditions including an acidic pH, a high alcoholic content, and growth inhibitory compounds such as fatty acids, phenolic acids and tannins. So how can O. oeni bacteria naturally present on the surface of grape berries acquire a natural resistance that will alleviate the effect of wine stresses? One mechanism displayed by O.

Serotonin receptors and cognitive behaviour--an update.

The serotonergic system appears to play a role in behaviors that involve a high cognitive demand and in memory improvement or recovery from an impaired cognitive performance. This is made evident after administration of 5-HT(2A/2C), and 5-HT4 receptor agonists, or 5-HT1A, 5-HT3 and probably 5-HT1B receptor antagonists. These serotonin receptor subtypes are localized on 'cognitive' pathways, with the hippocampus and frontal cortex as the main target structures.

Structure and orientation study of fusion peptide FP23 of gp41 from HIV-1 alone or inserted into various lipid membrane models (mono-, bi- and multibi-layers) by FT-IR spectroscopies and Brewster angle microscopy.

In the present work, we study the structure and the orientation of the 23 N-terminal peptide of the HIV-1 gp 41 protein (AVGIGALFLGFLGAAGSTMGARS) called FP23. The behaviour of FP23 was investigated alone at the air/water interface and inserted into various lipid model systems: in monolayer or multibilayers of a DOPC/cholesterol/DOPE/DOPG (6/5/3/2) and in a DMPC bilayer. PMIRRAS and polarized ATR spectroscopy coupled with Brewster angle microscopy and spectral simulations were used to precisely determine the structure and the orientation of the peptide in its environment as well as the lipid perturbations induced by the FP23 insertion.

A different recruitment of the lateral and basolateral amygdala promotes contextual or elemental conditioned association in Pavlovian fear conditioning.

Convergent data suggest dissociated roles for the lateral (LA) and basolateral (BLA) amygdaloid nuclei in fear conditioning, depending on whether a discrete conditioned stimulus (CS)-unconditional stimulus (US) or context-US association is considered. Here, we show that pretraining inactivation of the BLA selectively impaired conditioning to context. In contrast, inactivation of the LA disrupted conditioning to the discrete tone CS, but also either impaired or enhanced contextual conditioning, depending on whether the context was in the foreground or in the background.

Molecular mechanisms of tumor vascularization.

Tumor angiogenesis is a fast growing sub-domain of angiogenesis research and tumor biology. Basic mechanisms have been unraveled and many key players identified. For many years, tumor vascularization was explained solely by the ingrowth of new vessels into the tumor from preexisting one's.

Study of structure and orientation of mesentericin Y105, a bacteriocin from Gram-positive Leuconostoc mesenteroides, and its Trp-substituted analogues in phospholipid environments.

Mesentericin Y105 (Mes-Y105) is a bacteriocin secreted by Leuconostoc mesenteroides which is particularly active on Listeria. It is constituted by 37 residues and reticulated by one disulfide bridge. It has two W residues, W18 and W37, which can be studied by fluorescence.

Proton dynamics in the perchloric acid clathrate hydrate HClO4.5.5H2O.

In the perchloric acid clathrate hydrate HClO4.5.5H2O, the perchlorate anions are contained inside an aqueous host crystalline matrix, positively charged because of the presence of delocalized acidic protons.

Polymers suppress the inverse transfers of energy and the enstrophy flux fluctuations in two-dimensional turbulence.

The addition of minute amounts of a flexible polymer to two-dimensional turbulence produced in fast-flowing soap films affects large scales and small scales differently. For large scales, the inverse transfers of energy are suppressed. For small scales, where mean quantities are barely affected, the enstrophy flux fluctuations are significantly reduced, making the flow less chaotic.

Trace fear conditioning: a role for context?

Fear conditioning can be rapidly obtained over long trace intervals, but its specificity with respect to both time and stimulus is uncertain. Long-trace fear conditioning often parallels contextual conditioning, and it is sensitive to hippocampal lesions. These properties of trace conditioning are not directly addressed by timing models and multiple-time-scale models of conditioning.

Resistance to extinction is associated with impaired immediate early gene induction in medial prefrontal cortex and amygdala.

Extinction of classical fear conditioning is thought to involve activity-dependent potentiation of synaptic transmission in the medial prefrontal cortex (mPFC), resulting in the inhibition of amygdala-dependent fear responses. While many studies have addressed the mechanisms underlying extinction learning, it is unclear what determines whether extinction memory is consolidated or whether spontaneous recovery of the fear response occurs. Here we show, using a combined electrophysiological and immunocytochemical approach, that spontaneous recovery of conditioned fear in mice is associated with a prolonged expression of long-term depression of synaptic transmission in the mPFC and the failure of induction of the immediate-early genesc-Fos and zif268 in the mPFC and the basolateral nucleus of the amygdala.

e-Quantum chemistry free resources.

Among computational chemistry methods, quantum mechanics calculates geometries and electronic structures with accuracy especially for systems with electronic delocalization. The use of a multiconfigurational approach is able to treat highly degenerated states such as those occurring at the transition state in some chemical reactions. Moreover, an accurate description of potential energy surfaces can be obtained with the evaluation of the dynamic electron correlation effects by this approach.

Rewarding effects elicited by cocaine microinjections into the ventral tegmental area of C57BL/6 mice: involvement of dopamine D1 and serotonin1B receptors.

Rationale: The role of ventral tegmental area (VTA) in mediating the rewarding effects of cocaine has not been extensively studied.

Objectives: We used the intracranial self-administration (ICSA) procedure to assess the involvement of the VTA in the rewarding effects of cocaine, and the effect of dopamine (DA) D(1)- and serotonin (5-HT)(1B)-receptor antagonists on ICSA of cocaine.

Methods: Adult male C57BL/6 mice were stereotaxically implanted, unilaterally, with a guide cannula either 1.

Domain swapping in a COOH-terminal fragment of platelet factor 4 generates potent angiogenesis inhibitors.

A few peptide residues in structurally important locations often determine biological functions of proteins implicated in the regulation of angiogenesis. We have shown recently that the short COOH-terminal segment PF-4(47-70) derived from platelet factor 4 (PF-4) is the smallest sequence that conserves potent antiangiogenic activity in vitro and in vivo. Here we show that modified COOH-terminal PF-4 peptides containing the sequence ELR (or related DLR), a critical domain present in proangiogenic chemokines, surprisingly elicit several times greater antiangiogenic potential than the original peptide.

WWW small molecule modeling.

Computational chemistry and molecular modeling sites have proliferated on the Internet's world wide web. This paper provides present links to some of the more most useful ones for small organic molecule modeling, and offering free resources.

Differential effects of the dopamine D2/D3 receptor antagonist sulpiride on self-administration of morphine into the ventral tegmental area or the nucleus accumbens.

Rationale: The involvement of dopamine neurotransmission in opiate reward remains controversial.

Objective: To investigate the dopaminergic basis of opiate reward by comparing the effect of systemic injection of the D2/D3 antagonist sulpiride on morphine self-administration (ICSA) into the ventral tegmental area (VTA) or the nucleus accumbens (NAc)

Methods: BALB/c mice were unilaterally implanted with a guide cannula 1.5 mm above either the VTA or the NAc.

Physiological significance of the interleukin 1 receptor accessory protein.

Interleukin 1 receptor accessory protein (IL-1RAcP) is an essential signal-transducing component of the IL-1 receptor type I. The recent availability of IL-1RAcP-deficient (KO) mice allows to study the in vivo function of IL-1RAcP. Animals were injected intraperitoneally with rat recombinant IL-1beta (200 ng/mouse), lipopolysaccharide (LPS, 5 microg/mouse), or subjected to 1-hour restraint stress.

Modelling drugs and receptors using potentials: examples in the GPCRs' domain.

Shape complementarity, electrostatic and hydrophobic matching, were used to model drugs and receptors. From known experimental data on alpha1A/alpha2A-adrenergic ligands and alpha1A/alpha2A-adrenoceptors, a model for the ligand binding sites, based on the structure of bacteriorhodopsin as a template, was proposed and built. Agonists and antagonists have overlapping but different binding sites.

Prefrontal cortex long-term potentiation, but not long-term depression, is associated with the maintenance of extinction of learned fear in mice.

Considerable efforts have been made to identify changes of brain synaptic plasticity associated with fear conditioning. However, for both clinical applications and our fundamental understanding of memory processes, it appears also necessary to investigate synaptic plasticity related to extinction. We previously showed that extinction of freezing to a tone conditioned stimulus (CS; previously paired with footshock) in mice results in a sequence of depression and potentiation of synaptic efficacy in the medial prefrontal cortex (mPFC).

Gas spreading on a heated wall wetted by liquid.

This study deals with a simple pure fluid whose temperature is slightly below its critical temperature and whose density is nearly critical, so that the gas and liquid phases coexist. Under equilibrium conditions, such a liquid completely wets the container wall and the gas phase is always separated from the solid by a wetting film. We report a striking change in the shape of the gas-liquid interface influenced by heating under weightlessness where the gas phase spreads over a hot solid surface showing an apparent contact angle larger than 90 degrees.

Surface temperature dependence of rotational excitation of H(2) scattered from Pd(111).

Classical dynamics simulations are performed to study rotational excitation of H(2) scattered from Pd(111), taking into account energy exchange with surface phonons through a 3D surface oscillator model. We show that dynamic trapping, identified recently in the study of dissociation dynamics, plays a prominent role. The corresponding long interaction time due to several recollisions allows an efficient energy exchange between H(2) molecules and surface phonons.

Intrahippocampal injections of somatostatin dissociate acquisition from the flexible use of place responses.

Previous studies showed that injections of somatostatin (SS-14) into the hippocampus facilitate the acquisition of spatial tasks in mice. The present study was aimed at better understanding the learning and memory processes that could be affected by hippocampal SS-14 stimulation. Balb/c mice were submitted to a two-stage learning paradigm.

Polycyclic aromatic hydrocarbon 13C/12C ratio measurement in petroleum and marine sediments application to standard reference materials and a sediment suspected of contamination from the Erika oil spill.

This paper describes a simple and rapid sample preparation procedure allowing to measure the stable carbon isotopic composition of polycyclic aromatic hydrocarbons (PAHs) in petroleum and in sediments. The aromatic fraction is first purified and isolated on alumina and silica micro-columns. A high-performance liquid chromatography fractionation allows one then to isolate each aromatic family in order to limit coelutions between PAHs.