Imbalance in cerebral protein homeostasis: Effects on memory consolidation.

The long-standing hypothesis that memory consolidation is dependent upon de novo protein synthesis is based primarily on the amnestic effects of systemic administration of protein synthesis inhibitors (PSIs). Early experiments on mice showed that PSIs produced interference with memory consolidation that was dependent on the doses of PSIs, on the interval between drug injection and training, and, importantly, on the degree and duration of protein synthesis inhibition in the brain. Surprisingly, there is a conspicuous lack of information regarding the relationship between the duration of protein synthesis inhibition produced by PSIs and memory consolidation in the rat, one of the species most widely used to study memory processes.

Mouse corticospinal system comprises different functional neuronal ensembles depending on their hodology.

Background: Movement performance depends on the synaptic interactions generated by coherent parallel sensorimotor cortical outputs to different downstream targets. The major outputs of the neocortex to subcortical structures are driven by pyramidal tract neurons (PTNs) located in layer 5B. One of the main targets of PTNs is the spinal cord through the corticospinal (CS) system, which is formed by a complex collection of distinct CS circuits.

Paced mating increases the expression of μ opioid receptors in the ventromedial hypothalamus of male rats.

Paced mating induces a positive affective state which is blocked by naloxone, an opioid antagonist. Opioids are released in the medial preoptic area (mPOA) and other brain regions during sexual behavior and μ opioid receptors (MOR) are activated in males that copulate until ejaculation. The aim of the present study was to determine if paced mating increases the expression of MOR in areas involved in the control of sexual behavior in male rats.

Retrieval of Inhibitory Avoidance Memory Induces Differential Transcription of arc in Striatum, Hippocampus, and Amygdala.

Similar to the hippocampus and amygdala, the dorsal striatum is involved in memory retrieval of inhibitory avoidance, a task commonly used to study memory processes. It has been reported that memory retrieval of fear conditioning regulates gene expression of arc and zif268 in the amygdala and the hippocampus, and it is surprising that only limited effort has been made to study the molecular events caused by retrieval in the striatum. To further explore the involvement of immediate early genes in retrieval, we used real-time PCR to analyze arc and zif268 transcription in dorsal striatum, dorsal hippocampus, and amygdala at different time intervals after retrieval of step-through inhibitory avoidance memory.

PCR amplification of GC-rich DNA regions using the nucleotide analog N4-methyl-2'-deoxycytidine 5'-triphosphate.

GC-rich DNA regions were PCR-amplified with Taq DNA polymerase using either the canonical set of deoxynucleoside triphosphates or mixtures in which the dCTP had been partially or completely replaced by its N4-methylated analog, N4-methyl-2'-deoxycytidine 5'-triphosphate (N4me-dCTP). In the case of a particularly GC-rich region (78.9% GC), the PCR mixtures containing N4me-dCTP produced the expected amplicon in high yield, while mixtures containing the canonical set of nucleotides produced numerous alternative amplicons.

PPAR Agonists Promote the Differentiation of Porcine Bone Marrow Mesenchymal Stem Cells into the Adipogenic and Myogenic Lineages.

Purpose: The aim of this work was to evaluate the effect of PPAR agonists on the differentiation and metabolic features of porcine mesenchymal stem cells induced to the adipogenic or myogenic lineages.

Methods: Bone marrow MSCs from neonate pigs were isolated and identified by cell proliferation, cell surface markers or the gene expression of stem cells (CD44, CD90, CD105 or Oct4 and Nanog, respectively). Cells were differentiated into adipose or muscle cells and treated with the PPAR agonists; adipogenic and myogenic differentiation was promoted by adding these compounds.

Steroid Receptors and Aromatase Gene Expression in Different Brain Areas of Copulating and Sexually Sluggish Male Rats.

Introduction: Sexually sluggish (SS) males have been identified in several species of mammals including rats. These animals take more than 30 minutes to ejaculate; they do not ejaculate or do so inconsistently despite being tested repeatedly with sexually receptive females. Different brain areas and hormones play an important role in the control of male sexual behavior.

Hybridisation of N4-methylcytosine-containing amplicons on DNA microarrays.

5'-Cy5-labelled PCR amplicons containing the analogue base, N(4)-methylcytosine, instead of cytosines were compared in microarray hybridisation experiments with the corresponding amplicons containing the canonical set of bases, with respect to the intensity of the fluorescence signal obtained, and cross hybridisation to non-corresponding probes. In general, higher hybridisation temperatures resulted in reduced signal intensities, particularly in the case of the N(4)-methylcytosine containing amplicons. At the lower hybridisation temperatures tested (40 °C, 30 °C), these modified amplicons gave about equal or stronger fluorescence signal than the corresponding regular amplicons.

Capacity of N4-methyl-2'-deoxycytidine 5'-triphosphate to sustain the polymerase chain reaction using various thermostable DNA polymerases.

The dCTP analog N4-methyl-2'-deoxycytidine 5'-triphosphate (N4medCTP) was evaluated for its performance in the polymerase chain reaction (PCR). Using the HotStart Taq DNA polymerase with a standard thermal protocol, test segments 85 or 200 bp long were amplified equally well using dCTP or N4medCTP:dCTP mixtures ranging in molar ratio from 3:1 to 10:1, while complete replacement of dCTP by N4medCTP gave clearly lower amplicon yields and higher Cq values. Comparable yields with N4medCTP or dCTP were achieved only by using a slowdown protocol.

In vitro conversion of ß-carotene to retinal in bovine rumen fluid by a recombinant ß-carotene- 15, 15'-monooxygenase.

Pasture-fed cattle yield carcasses with yellow fat; consumers often reject the resulting meat products because they assume they come from old and/or culled animals. Recombinant bacteria expressing beta-carotene 15, 15'-monooxygenase, introduced into the rumen of the animal, might help to reduce the coloration since this enzyme converts carotene to retinal, thereby eliminating the source of yellowness. The goal of this work was to evaluate the effect of a recombinant beta-carotene 15, 15'-monooxygenase (BCMO1) from Gallus gallus, expressed in Escherichia coli.

Time course of retinal degeneration associated with the absence of 1, 4, 5-inositol trisphosphate receptor in Drosophila melanogaster.

The absence of the inositol trisphosphate receptor is associated with a gradual retinal degeneration in Drosophila melanogaster. To characterize the time-course profile of this process, mosaic flies expressing a null allele of the itp gene in the eye were studied by electroretinograms and electronic microscopy. Membrane contour alterations, disrupted mitochondria, altered morphology and even loss of photoreceptors were increased progressively starting 5 d after hatching, were more evident during days 10-15 and promoted highly disorganized structures thereafter.

MCF-7 breast carcinoma cells express ryanodine receptor type 1: functional characterization and subcellular localization.

Breast carcinoma-derived MCF-7 cells are frequently used in biomedical research. However, few reports exist regarding the characterization of signaling mechanisms in these cancerous cells involved in intracellular Ca(2+) dynamics. Consequently, the aim of these experiments was to characterize the ryanodine receptor/Ca(2+) release channel (RyR) present in MCF-7 cells.

Enhanced inhibitory avoidance learning prevents the long-term memory-impairing effects of cycloheximide, a protein synthesis inhibitor.

Interference with activity of numerous cerebral structures produces memory deficiencies; in many instances, however, when animals are over-trained such interference becomes innocuous. Systemic administration of protein synthesis inhibitors impairs long-term retention; this effect has been interpreted to mean that protein synthesis is required for memory consolidation, though little is known about the effect of protein synthesis inhibitors on memory of enhanced learning in the rat. To further analyze the protective effect of enhanced learning against amnesic treatments, groups of Wistar rats were trained in a one-trial step-through inhibitory avoidance task, using different intensities of foot-shock during training.

Molecular basis for the impaired function of the natural F112L sorcin mutant: X-ray crystal structure, calcium affinity, and interaction with annexin VII and the ryanodine receptor.

The penta-EF hand protein sorcin participates in the modulation of Ca2+-induced calcium-release in the heart through the interaction with several Ca2+ channels such as the ryanodine receptor. The modulating activity is impaired in the recently described natural F112L mutant. The F112 residue is located at the end of the D helix next to Asp113, one of the calcium ligands in the EF3 hand endowed with the highest affinity for the metal.

Cloning of the bovine beta-carotene-15,15'-oxygenase and expression in gonadal tissues.

Beta-carotene-15,15'-oxygenase (betaCO), found mainly in intestinal mucosa and liver, is the enzyme responsible for cleaving beta-carotene into retinal, which can be used or stored at these sites or carried by the bloodstream to different target cells within the body. We isolated the cDNA for bovine betaCO and demonstrated its expression in gonadal tissues. A cDNA of 2130 base pairs (bp) was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE), using degenerate oligonucleotides; the deduced protein shared an identity of 75% with its homologues from other mammalian species.

The foot structure from the type 1 ryanodine receptor is required for functional coupling to store-operated channels.

In the present study we have explored structural determinants of the functional interaction between skeletal muscle ryanodine receptor (RyR1) and transient receptor potential channel 1 (TRPC1) channels expressed in Chinese hamster ovary cells. We have illustrated a functional interaction between TRPC1 channels and RyR1 for the regulation of store-operated calcium entry (SOCE) initiated after releasing calcium from a caffeine-sensitive intracellular calcium pool. RNA interference experiments directed to reduce the amount of TRPC1 protein indicate that RyR1 associates to at least two different types of store-operated channels (SOCs), one dependent and one independent of TRPC1.

Regulation of cardiac excitation-contraction coupling by sorcin, a novel modulator of ryanodine receptors.

Activation of Ca2+ release channels/ryanodine receptors (RyR) by the inward Ca2+ current (I(Ca)) gives rise to Ca(2+)-induced Ca2+ release (CICR), the amplifying Ca2+ signaling mechanism that triggers contraction of the heart. CICR, in theory, is a high-gain, self-regenerating process, but an unidentified mechanism stabilizes it in vivo. Sorcin, a 21.

Sorcin inhibits calcium release and modulates excitation-contraction coupling in the heart.

Activation of Ca2+ release channels/ryanodine receptors (RyR) by the inward Ca2+ current (ICa) gives rise to Ca2+-induced Ca2+ release (CICR), the amplifying Ca2+ signaling mechanism that triggers contraction of the heart. CICR, in theory, is a high-gain, self-regenerating process, but an unidentified mechanism stabilizes it in vivo. We reported previously (Lokuta, A.

Basal activity of GIRK5 isoforms.

G protein-coupled inwardly rectifying K(+) channels (GIRK or Kir3) form functional heterotetramers gated by Gbetagamma subunits. GIRK channels are critical for functions as diverse as heart rate modulation and neuronal post-synaptic inhibition. GIRK5 (Kir3.