Enterococcus faecalis: implications for host health.

The microbiota represents a crucial area of research in maintaining human health due to its potential for uncovering novel biomarkers, therapies, and molecular mechanisms relevant to population identification and experimental model characterization. Among these microorganisms, Enterococcus faecalis, a Gram-positive bacterium found in the gastrointestinal tract of humans and animals, holds particular significance. Strains of this bacterial species have sparked considerable debate in the literature due to their dual nature; they can either be utilized as probiotics in the food industry or demonstrate resistance to antibiotics, potentially leading to severe illness, disability, and death.

Differential expression of alpha-synuclein in the hippocampus of SHR and SLA16 isogenic rat strains.

Two inbred strains, Lewis (LEW) and Spontaneously Hypertensive Rats (SHR), are well-known for their contrasting behavior related to anxiety/emotionality. Studies with these two strains led to the discovery of the Quantitative Trait Loci (QTL) on chromosome 4 (Anxrr16). To better understand the influences of this genomic region, the congenic rat strain SLA16 (SHR.

Genetic effects in a progressive model of parkinsonism induced by reserpine.

Objective And Methods: We investigated the locomotor, emotional, physiological, and neurobiological effects induced by low-dose reserpine repeated treatment (0.1 mg/kg; 14 injections) in males from the Lewis (LEW), Spontaneously Hypertensive Rats (SHR), and SHR.LEW-(D4Rat76-D4Mgh11) (SLA16) isogenic rat strains, which have different genetic backgrounds on chromosome 4.

Hunting for Genes Underlying Emotionality in the Laboratory Rat: Maps, Tools and Traps.

Scientists have systematically investigated the hereditary bases of behaviors since the 19th century, moved by either evolutionary questions or clinically-motivated purposes. The pioneer studies on the genetic selection of laboratory animals had already indicated, one hundred years ago, the immense complexity of analyzing behaviors that were influenced by a large number of small-effect genes and an incalculable amount of environmental factors. Merging Mendelian, quantitative and molecular approaches in the 1990s made it possible to map specific rodent behaviors to known chromosome regions.

The influence of chromosome 4 on high ethanol consumption and blood pressure.

The Spontaneously Hypertensive Rats (SHR) strain was developed through selective breeding for high systolic blood pressure. In our laboratory, we established a congenic rat strain named SHR.Lewis-Anxrr16 (SLA16).

Agmatine improves olfactory and cognitive deficits in Spontaneously Hypertensive Rats (SHR): An animal model of Attention Deficit Hyperactivity Disorder (ADHD).

Attention Deficit Hyperactivity Disorder (ADHD) is a highly prevalent and disabling disorder that frequently persists into adulthood. Many patients are considered nonresponders to typical pharmacological treatments due to insufficient symptoms' reduction or the inability to tolerate the side effects of these medications. Agmatine is an endogenous neuromodulator with emotional- and cognitive-enhancing properties that arises as a promising agent to manage several Central Nervous System disorders.

Changes in the mesocorticolimbic pathway after low dose reserpine-treatment in Wistar and Spontaneously Hypertensive Rats (SHR): Implications for cognitive deficits in a progressive animal model for Parkinson's disease.

Reserpine (RES) is an irreversible inhibitor of VMAT2 used to study Parkinson's disease (PD) and screening for antiparkinsonian treatments in rodents. Recently, the repeated treatment with a low dose of reserpine was proposed as a model capable of emulating progressive neurochemical, motor and non-motor impairments in PD. Conversely, compared to Wistar rats, Spontaneously Hypertensive Rats (SHR) are resistant to motor changes induced by repeated treatment with a low dose of RES.

Temporal development of neurochemical and cognitive impairments following reserpine administration in rats.

The systemic administration of low reserpine (RES) doses (0.1-1.0 mg/kg) has been proposed as a valuable rat model for the study of non-motor symptoms of Parkinson's disease (PD).

The influence of chromosome 4 on metabolism and spatial memory in SHR and SLA16 rat strains.

The Spontaneously Hypertensive Rat (SHR) has been proposed as a good model to study the pathways related to neurodegenerative diseases and glucose intolerance. Our research group developed the SLA16 (SHR.LEW-Anxrr16) congenic strain, which is genetically identical to the SHR strain, except for a locus on chromosome 4 (DGR).

Effects of Repeated Treatment with Midazolam in SHR and SLA16 Rat Strains in the Triple Test.

We exposed male and female rats of SHR (Spontaneously Hypertensive Rats) and SLA16 (SHR.LEW-Anxrr16) strains, in a non-drugged state, for five consecutive days to the Triple Test (experiment 1); or after repeated treatment with midazolam (MDZ), for four consecutive days. The fifth day was performed without treatment (experiment 2).

The Quinpirole Hypolocomotive Effects are Strain and Route of Administration Dependent in SHR and SLA16 Isogenic Rats.

The SHR and SLA16 inbred strains present behavioral differences in anxiety/emotionality that could be under the influence of dopaminergic neurotransmission. In order to investigate the role of D2 receptors in modulating such differences, an agonist (quinpirole) and an antagonist (haloperidol) of this receptor were administered, either via systemic injection (IP), or microinjected into the ventral area of the hippocampus (vHIP). Quinpirole and haloperidol IP decreased locomotor activity, only in SLA16 rats in the open-field (OF), and in both strains in the elevated plus-maze (EPM).

Variants in SNCA Gene Are Associated with Parkinson's Disease Risk and Cognitive Symptoms in a Brazilian Sample.

Genetic susceptibility contributes to the etiology of sporadic Parkinson's Disease (PD) and worldwide studies have found positive associations of polymorphisms in the alpha-synuclein gene (SNCA) with the risk for PD. However, little is known about the influence of variants of SNCA in individual traits or phenotypical aspects of PD. Further, there is a lack of studies with Latin-American samples.

Effects of physical exercise and social isolation on anxiety-related behaviors in two inbred rat strains.

We investigated the effects of physical exercise (PE) on locomotor activity and anxiety-like behavior in Lewis (LEW) and Spontaneously Hypertensive Rats (SHR) male rats. Rats received either four weeks of forced training, 5days/week, on a treadmill (experiment 1) or were given 21days of free access to running wheels (experiment 2). We also tested the effects of social isolation (SI) (seven days of isolation - experiment 3) on behavior.

Spontaneously Hypertensive Rats (SHR) Are Resistant to a Reserpine-Induced Progressive Model of Parkinson's Disease: Differences in Motor Behavior, Tyrosine Hydroxylase and α-Synuclein Expression.

Reserpine is an irreversible inhibitor of vesicular monoamine transporter-2 (VMAT2) used to study Parkinson's disease (PD) and screening for antiparkinsonian treatments in rodents. Recently, the repeated treatment with a low-dose of reserpine was proposed as a progressive model of PD. Rats under this treatment show progressive catalepsy behavior, oral movements and spontaneous motor activity decrement.

Sex and estrous cycle influence diazepam effects on anxiety and memory: Possible role of progesterone.

Studies with rodents and humans show the relationship between female sex hormones and cognitive/emotional tasks. However, despite the greater incidence of anxiety disorders in women, the data are still inconclusive regarding the mechanisms related to this phenomenon. We evaluated the effects of a classical anxiolytic/amnestic drug (diazepam; DZP) on female (at different estrous cycle phases) and male rats tested in the plus-maze discriminative avoidance task (PMDAT), that allows the concomitant evaluation of memory and anxiety-like behavior.

Genetic evidence for chromosome 4 loci influencing learning and memory.

The Lewis (LEW) and SHR (Spontaneously Hypertensive Rats) inbred rat strains differ in several anxiety/emotionality and learning/memory-related behaviors. We aimed to search quantitative trait locus (QTL) that influence these behaviors and confirm their effects in a congenic rat strain SLA16 (SHR.LEW.

Diazepam effects on aversive memory retrieval and extinction: Role of anxiety levels.

Benzodiazepines (BDZs) are anxiolytic drugs that impair memory acquisition. Previous studies using the plus-maze discriminative avoidance task (PMDAT, which assesses memory and anxiety concomitantly) indicated that the effects of BDZs on anxiety and acquisition are related to each other. The possible influence of the anxiolytic action of BDZs on their effects on memory retrieval and extinction are poorly understood.

Estrogen levels modify scopolamine-induced amnesia in gonadally intact rats.

Previous studies suggested that estrogen plays a role in cognitive function by modulating the cholinergic transmission. However, most of the studies dealing with this subject have been conducted using ovariectomized rats. In the present study we evaluated the effects of physiological and supra-physiological variation of estrogen levels on scopolamine-induced amnesia in gonadally intact female rats.

Cognitive, motor and tyrosine hydroxylase temporal impairment in a model of parkinsonism induced by reserpine.

Studies have suggested that cognitive deficits can precede motor alterations in Parkinson's disease (PD). However, in general, classic animal models are based on severe motor impairment after one single administration of neurotoxins, and thereby do not express the progressive nature of the pathology. A previous study showed that the repeated administration with a low dose (0.

Repeated treatment with a low dose of reserpine as a progressive model of Parkinson's disease.

Animal models are widely used to study alterations caused by Parkinson's disease (PD). However, in general, pharmacological models do not express the progressive nature of the disease, being characterized by immediate severe motor impairment after a single dose of the drug. Reserpine administration in rodents has been suggested as a pharmacological model of PD based on the effects of this monoamine-depleting agent on motor activity.

Antidepressants differentially modify the extinction of an aversive memory task in female rats.

Treatment of major depression, posttraumatic stress disorder and other psychopathologies with antidepressants can be associated with improvement of the cognitive deficits related to these disorders. Although the mechanisms of these effects are not completely elucidated, alterations in the extinction of aversive memories are believed to play a role in these psychopathologies. We have recently verified that female rats present low levels of extinction when submitted to the plus-maze discriminative avoidance task.

The influence of sex and estrous cycle on QTL for emotionality and ethanol consumption.

The inbred rat strains Lewis (LEW) and Spontaneously Hypertensive Rats (SHR) differ with respect to several emotionality- and ethanol intake-related behaviors, one of which (inner locomotion in the open field; OF) is strongly influenced by a locus (Anxrr16) on chromosome (Chr) 4. We aimed to further investigate the influence of Chr 4 on these behaviors and to evaluate the role of the estrous cycle in QTL expression. LEW females and SHR males were intercrossed to produce F1 and F2 rats (96-97/sex), which were then tested in the OF, light-dark box (LDB), forced swimming test (FST), and an ethanol consumption procedure (ECP).

Pre-training anandamide infusion within the basolateral amygdala impairs plus-maze discriminative avoidance task in rats.

Endocannabinoids (eCBs) modulate a variety of brain functions via activation of the widely expressed CB1 receptor. One site of high density of this receptor is the basolateral amygdala (BLA), a structure involved in the formation of aversive memories. The activation and blockade of CB1 receptors by systemic or hippocampal drug administrations have been shown to modify memory processing.

Absence of repeated-trial tolerance to the anxiolytic-like effects of chlordiazepoxide in the rat triple test.

The triple test, recently developed to assess anxiety-related behaviors in rodents, combines three widely used behavioral tests: the open field (OF), elevated plus maze (EPM) and light/dark box (LDB). The EPM and LDB, individually, are normally sensitive to the anxiolytic effects of benzodiazepines only in the first trial, due to the phenomenon of one-trial tolerance, which limits their use in longitudinal studies. The main objective of the present investigation was to verify whether the anxiolytic-like effects of chlordiazepoxide (CDZ), previously observed in naive animals submitted to the triple test, would persist after repeated testing.