Trained Rats Research Articles

Synchronized excitability in a network enables generation of internal neuronal sequences

Hippocampal place field sequences are supported by sensory cues and network internal mechanisms. In contrast, sharp-wave (SPW) sequences, theta sequences, and episode field sequences are internally generated. The relationship of these sequences to memory is unclear. SPW sequences have been shown to support learning and have been assumed to also support episodic memory. Conversely, we demonstrate these SPW sequences were present in trained rats even after episodic memory was impaired and after other internal sequences - episode field and theta sequences - were eliminated. SPW sequences did not support memory despite continuing to 'replay' all task-related sequences - place- field and episode field sequences. Sequence replay occurred selectively during synchronous increases of population excitability -- SPWs. Similarly, theta sequences depended on the presence of repeated synchronized waves of excitability - theta oscillations. Thus, we suggest that either intermittent or rhythmic synchronized changes of excitability trigger sequential firing of neurons, which in turn supports learning and/or memory.

Effects of Tongue Force Training on Bulbar Motor Function in the Female SOD1-G93A Rat Model of Amyotrophic Lateral Sclerosis

Background. The use of exercise in amyotrophic lateral sclerosis (ALS) is controversial. Although moderate exercise appears to be beneficial for limb muscles in ALS, the effects of exercise on bulbar muscles such as the tongue have not been studied. Objective. To determine the effects of tongue force training on bulbar motor function in the SOD1-G93A rat model of ALS. Methods. We compared the effects of tongue force training on bulbar motor function and neuromuscular junction innervation in female SOD1-G93A rats and age-matched female wild-type controls. Half of each group underwent afternoon tongue force training sessions, and all rats were tested under minimal force conditions in the mornings. Results. Tongue force did not differ between the SOD1-G93A rats and healthy controls during the morning testing sessions, nor was it affected by training. Surprisingly, decreases in tongue motility, the number of licks per session, and body weight were greater in the tongue force–trained SOD1-G93A rats. Forelimb grip force, survival, and denervation of the genioglossus (GG) muscle did not differ between the trained and untrained SOD1-G93A rats. GG innervation was correlated with changes in tongue force but not tongue motility in SOD1-G93A rats at end stage. Conclusions. The results indicate a potential deleterious effect of tongue force training on tongue motility in female SOD1-G93A rats. The lack of a relationship between GG innervation and tongue motility suggests that factors other than lower–motor neuron integrity likely accounted for this effect.

Behavioral representation of cost and benefit balance in rats

Decision making is dependent upon individual motivation. Previous studies showed that animals with higher levels of motivation are more likely to invest more time to acquire larger rewards rather than acquiring smaller rewards with less time to wait. However, little is known about how this motivation mediates the cognitive effort animals devote upon making said decisions in detail. In the present study, we investigated the behavioral response in a goal-directed action under a differential reward schedule by training rats to perform a “Do more, get more” (DM-GM) task using a nosepoke operandum when longer nosepoke durations resulted in correspondingly larger rewards. In general, the subjects learned this DM-GM rule and reached a steady behavioral state within 15days. During the training stage, the rats found the most cost-effective action choice and behaved according to that guideline more frequently than other possible actions. In addition, when the cost-benefit ratio changed, the rats again found a new most cost-effective choice to obtain maximum rewards. Our results demonstrate that there is a “balance point” of cost and benefit in rat valuation system and that this “balance point” not only guides the rats to make the appropriate decision, but that this point can be modified upon new situations to choose a newer optimum action plan.

KEBERHASILAN PENANGKAPAN TIKUS (TRAP SUCCESS) DAN INDEKS PINJAL DI DESA KAYUKEBEK KABUPATEN PASURUAN TAHUN 2016

Plague suspect and high flea index is potential transmission of pes. Therefore, it is necessary to conduct rodent and flea observation as an attempt of awareness early occurrence of Extraordinary Events. The purpose of this study was to determine the trap success of flea index. This is a descriptive study by using survey method with cross sectional approach. The study was conducted in Surorowo hamlet, Kayukebek village, Tutur sub district, Pasuruan in February to June 2016. The result showed 29 rats were trapped. The rats found were 17 Rattus tanezumi, 11 Rattus Rattus exulans and one niviventer.The fleas trapped were 17 Xenopsylla cheopis and 3 Stivalius cognatus. 5.67% trap success was carried out in homes, 3.67% in gardens and 0.25% in jungles. Public fleasindex was 0.68; Special flea index of Xenopsylla cheopis was 0.58. From the results above, most of the rats trapped was from Rattus tanezumi type, most trapped fleas was from Xenopsylla cheopis type. Trap success inside and outside homes was categorized as low. Common fleas Index and specific flea index of Xenopsylla cheopis was below standard. There is a need for the provision of number on the trap, increasing the number of traps and training rats catchers. The community is expected to perform trapping independently by providing mousetrap on their own, saving crops in a closed place and providing a closed trash can. Further research on various types of bait can be carried out to know the type of bait rats like. Keywords : trap success and flea index

Combination of Weight-Bearing Training and Anti-MSTN Polyclonal Antibody Improve Bone Quality In Rats.

Weight-bearing exercise is beneficial to bone health. Myostatin (MSTN) deficiency has a positive effect on bone formation. We wondered if a combination of weight-bearing training and polyclonal antibody for MSTN (MsAb) would augment bone formation to a greater degree than single treatment. In this study, rats were randomly assigned to four groups: Control, weight-bearing training (WT), MsAb, and WT+MsAb. The trained rats ran at 15 m/min bearing with 35% of their body weight, 40 min/day (2 min of running followed by 2 min of rest), 6 days/week, for 8 weeks. The rats with MsAb were injected once a week with MsAb for 8 weeks. MicroCT analysis showed that compared with the MsAb group, WT+MsAb significantly enhanced cortical bone mineral density (BMD) (p < .01), bone volume over total volume (BV/TV) (p < .01), trabecular thickness (p < .05), and reduced trabecular separation (Tb.Sp) (p < .01). Compared with the WT group, WT+MsAb significantly increased trabecular BMD (p < .05), BV/TV (p < .05), and decreased Tb.Sp (p < .05). Three-point bending test demonstrated that MsAb failed to improve bone biomechanical properties (p > .05), weight-bearing training significantly increased energy absorption (p < .05) and elastic modulus (p < .05). However, when they combined, biomechanical properties including maximum load (p < .05), stiffness (p < .05), elastic modulus (p < .01) and energy absorption (p < .01) were all significantly enhanced. In conclusion, the combination of weight-bearing training and MsAb have a greater positive effect on bone than treatment with either MsAb or weight-bearing training alone, suggesting that resistance training in combination with MSTN antagonists could be an effective approach for improving bone health and reducing osteoporosis risk.

Attenuation of exercise effect on inflammatory responses via novel role of TLR4/PI3K/Akt signaling in rat splenocytes

Moderate exercise diminishes proinflammation cytokine production in various types of immune cells, but the intracellular signaling pathways involved are not completely understood. Phosphoinositide 3-kinase (PI3K)/Akt, a crucial downstream protein of toll-like receptor 4 (TLR4), may modulate inflammation. The present study aimed to investigate the effects of exercises on lipopolysaccharide (LPS)-stimulated inflammatory response in splenocytes and to explore potential mechanisms of the PI3K/Akt pathway. Male rats were divided into sedentary and exercise groups. Animals in the exercise group underwent endurance training 30 min/day, 7 days/wk, at the speed of 20 m/min on a treadmill for 1 wk. Here, we showed that exercise 1) attenuated TLR4, 2) increased PI3K/phospho-Akt (p-Akt), and 3) diminished phospho-nuclear factor-κB (p-NF-κB) expression. In addition, administration of splenocytes isolated from trained rats with LPS in vitro showed 1) reduced tumor necrosis factor (TNF-α), interleukin 6 (IL-6), and nitric oxide secretion and 2) decreased splenocyte proliferation. The plasma corticosterone (CCS) level in the exercise group was higher than that in the sedentary group. We confirmed that CCS down-regulated TNF-α and IL-6 secretion in response to LPS in rat splenocytes. Dexamethasone also significantly attenuated LPS-evoked release of TNF-α and IL-6 in a dose-dependent manner. These findings suggested that exercise dampened the secretion of inflammation mediators probably through partial inhibition of TLR4 and p-NF-κB and activation of PI3K/p-Akt expression in the spleen.

Effect of Different Exercise Intensities on the Myotendinous Junction Plasticity.

Myotendinous junctions (MTJs) are anatomical regions specialized in transmission of contractile strength from muscle to tendon and, for this reason, a common site where acute injuries occur during sport activities. In this work we investigated the influence of exercise intensity on MTJ plasticity, as well as on the expression of insulin-like growth factor 1 (IGF-1) and transforming growth factor beta (TGF-β) and their receptors in muscle and tendon. Three groups of rats were analyzed: control (CTRL), slow-runner (RUN-S) and fast-runner (RUN-F) trained using a treadmill. Ultrastructural and morphometric analyses of distal MTJs from extensor digitorum longus muscles have been performed. Contractile strength and hypertrophy were investigated by using in vivo tension recordings and muscle cross-sectional area (CSA) analysis, respectively. mRNA levels of PGC-1α, vinculin, IGF-1Ea and TGF-β have been quantified in muscle belly, while IGF-1Ea, TGF-β and their receptors in tendon. Morphometry revealed an increased MTJ complexity and interaction surface between tissues in trained rats according to training intensity. CSA analysis excluded hypertrophy among groups, while muscle strength was found significantly enhanced in exercised rats in comparison to controls. In muscle tissue, we highlighted an increased mRNA expression of PGC-1α and vinculin in both trained conditions and of TGF-β in RUN-F. In tendon, we mainly noted an enhancement of TGF-β mRNA expression only in RUN-F group and a raise of Betaglycan tendon receptor mRNA levels proportional to exercise intensity. In conclusion, MTJ plasticity appears to be related to exercise intensity and molecular analysis suggests a major role played by TGF-β.

Inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear

Promoting extinction of fear memory is the main treatment of fear disorders, especially post-traumatic stress disorder (PTSD). However, fear extinction is often incomplete in these patients. Our previous study had shown that Rac1 activity in hippocampus plays a crucial role in the learning of contextual fear memory in rats. Here, we further investigated whether Rac1 activity also modulated the extinction of contextual fear memory. We found that massed extinction obviously upregulated hippocampal Rac1 activity and induced long-term extinction of contextual fear in rats. Intrahippocampal injection of the Rac1 inhibitor NSC23766 prevents extinction of contextual fear in massed extinction training rats. In contrast, long-spaced extinction downregulated Rac1 activity and caused less extinction. And Rac1 activator CN04-A promotes extinction of contextual fear in long-spaced extinction rats. Our study demonstrates that inhibition of Rac1 activity in the hippocampus impaired extinction of contextual fear, suggesting that modulating Rac1 activity of the hippocampus may be promising therapy of fear disorders.

Long-term leucine supplementation aggravates prolonged strenuous exercise-induced cardiovascular changes in trained rats.

What is the central question of this study? Can long-term leucine supplementation prevent prolonged strenuous endurance exercise induced cardiac injury? What is the main finding and its importance? Prolonged endurance exercise does not seem to exceed cardiac energetic capacity, hence it does not represent an energy threat to this organ, at least in trained subjects. However, it may induce, in susceptible individuals, a state of cardiac electrical instability, which has been associated with ventricular arrhythmias and sudden cardiac death. This situation might be worsened when combined with leucine supplementation, which leads to increased blood pressure and cardiac injury. Leucine supplementation failed to prevent cardiac fatigue symptoms and may aggravate prolonged strenuous exercise-induced cardiovascular disturbances in trained rats. Observational studies have raised concerns that prolonged strenuous exercise training may be associated with increased risk of cardiac arrhythmia and even primary cardiac arrest or sudden death. It has been demonstrated that leucine can reduce prolonged exercise-induced muscle damage and accelerate the recovery process. The aim of this study was to investigate the effects of prolonged strenuous endurance exercise on cardiovascular parameters and biomarkers of cardiac injury in trained adult male rats and assess the use of leucine as an auxiliary substance to prevent the likely cardiac adverse effects caused by strenuous exercise. Twenty-four male Wistar rats were randomly allocated to receive a balanced control diet (18% protein) or a leucine-rich diet (15% protein plus 3% leucine) for 6 weeks. The rats were submitted to 1h of exercise, 5days per week for 6weeks. Three days after the training period, the rats were submitted to swimming exercise until exhaustion, and cardiac parameters were assessed. Exercising until exhaustion significantly increased cardiac biomarker levels, cytokines and glycogen content inhibited protein synthesis signalling and led to cardiac electrical disturbances. When combined with exercise, leucine supplementation led to greater increases in the aforementioned parameters and also a significant increase in blood pressure and protein degradation signalling. We report, for the first time, that leucine supplementation not only fails to prevent cardiac fatigue symptoms, but may also aggravate prolonged strenuous exercise-induced cardiovascular disturbances in trained rats. Furthermore, we find that exercising until exhaustion can cause cardiac electrical disturbances and damage cardiac myocytes.

Efeitos da Suplementação de Fibras Solúveis, Dieta de Cafeteria e Exercício Físico sobre Aorta Torácica de Ratos

As fibras alimentares vêm despertando interesse de especialistas das áreas de nutrição e saúde. Elas contribuem para a redução do risco de desenvolvimento de doenças cardiovasculares, além de ajudar no processo de perda de peso, principalmente quando seu consumo é associado à atividade física. Entretanto existem poucos trabalhos associando o uso de fibras solúveis à uma dieta hipercalórica e ao exercício físico. Assim, objetivo desse estudo foi investigar os efeitos das fibras solúveis sobre a aorta torácica e perfil lipídico de ratos machos wistar sedentários e treinados submetidos à dieta de cafeteria. Os parâmetros morfométrico e estereológico: espessura íntima-média e densidade de volume do músculo liso e do colágeno e o perfil lipídico foram determinados. Não foram observadas alterações na espessura da parede vascular, densidade de volume do músculo liso e colágeno. No entanto, o perfil lipídico apresentou-se alterado com o uso da dieta de cafeteria. A fibra alimentar associada ao treinamento aeróbio e a uma dieta balanceada apresentou resultado eficaz, não alterando a morfologia do vaso.

Motor Training Promotes Both Synaptic and Intrinsic Plasticity of Layer II/III Pyramidal Neurons in the Primary Motor Cortex.

Motor skill training induces structural plasticity at dendritic spines in the primary motor cortex (M1). To further analyze both synaptic and intrinsic plasticity in the layer II/III area of M1, we subjected rats to a rotor rod test and then prepared acute brain slices. Motor skill consistently improved within 2 days of training. Voltage clamp analysis showed significantly higher α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/N-methyl-d-aspartate (AMPA/NMDA) ratios and miniature EPSC amplitudes in 1-day trained rats compared with untrained rats, suggesting increased postsynaptic AMPA receptors in the early phase of motor learning. Compared with untrained controls, 2-days trained rats showed significantly higher miniature EPSC amplitude and frequency. Paired-pulse analysis further demonstrated lower rates in 2-days trained rats, suggesting increased presynaptic glutamate release during the late phase of learning. One-day trained rats showed decreased miniature IPSC frequency and increased paired-pulse analysis of evoked IPSC, suggesting a transient decrease in presynaptic γ-aminobutyric acid (GABA) release. Moreover, current clamp analysis revealed lower resting membrane potential, higher spike threshold, and deeper afterhyperpolarization in 1-day trained rats—while 2-days trained rats showed higher membrane potential, suggesting dynamic changes in intrinsic properties. Our present results indicate dynamic changes in glutamatergic, GABAergic, and intrinsic plasticity in M1 layer II/III neurons after the motor training.

Intermittent Hypoxia Increases Mitochondrial Dynamics and Biogenesis After Eccentric Exercise-Induced Muscle Damage in Trained Rats

Mitochondria play a key role in (and are modulated by) exercise physiology, response to hypoxia and to cellular damage. Consequently, hypobaric hypoxia and exercise could play an important role in muscle damage and recovery through mitochondrial regulation. PURPOSE: To analyze the mitochondrial biogenesis and dynamics in eccentric-exercise induced muscle damage (EEIMD) and its recovery with intermittent hypobaric hypoxia (IHH), alone or combined with light exercise. METHODS: Muscle injury was induced by downhill running to forty-eight Sprague-Dawley trained rats. They were divided into three groups: (1) Ctrl (passive recovery); (2) HYP (exposed to IHH: 4-hour session per day, at 4,000 m); and (3) EHYP (IHH + light aerobic exercise). Each group was analyzed 1, 3, 7 and 14 days after the muscle damage. The following proteins were determined by Western Blotting: PGC-1α, TFAM, TOM20 (proteins related to biogenesis), Mfn1, OPA-1 and DRP-1 (proteins related to mitochondrial fusion and fission) and Sirt3 (protein related to biogenesis and oxidative stress). All results were normalised to the Ctrl group. RESULTS: 7 days after the damage induction, both HYP and EHYP groups showed significant increased levels of biogenesis markers PGC-1α (161 and 159%, respectively) and TOM20 (156 and 147%) compared with the Ctrl group, while only EHYP had a significant increase of TFAM. At t14 only EHYP rats had increased levels of PGC-1α (128%), but both HYP and EHYP groups showed increased TFAM (153 and 155%) and TOM20 (145 and 144%). Sirt3 was significantly increased in HYP t03 (200%) and in the EHYP group at t07 (127%). Regarding to the mitochondrial fusion proteins, HYP and EHYP rats had increased levels of OPA-1 at t07 (171% both) and t14 (136 and 128%), while Mfn1 was only increased at t14 in EHYP (158%). On the other hand, DRP-1 appeared elevated in HYP t07 (133%) and EHYP t14 (162%) groups. These differences had a p-value <0.05. CONCLUSIONS: after an EEIMD protocol, IHH exposure increased mitochondrial biogenesis and dynamics, as well as Sirt3 protein. When combined with light aerobic exercise, these increments were more consistent and took place in a later stage of the recovery. Taking into account the important role of the mitochondria in the muscle cell, the results suggest that these protocols can improve the muscle damage recovery.

Effect of previous strength training episode and retraining on facilitation of skeletal muscle hypertrophy and contractile properties after long-term detraining in rats.

In the present study, we investigated the effects of previous strength training and retraining following long-term cessation of exercise on muscle mass and contractile properties. Female Sprague-Dawley rats (n=24) aged eight weeks were randomly assigned one of the four groups: control (CON), detraining (DT), training (TR), and retraining (RT). The training regimen consisted of climbing ladder 5×3 sets, once every third day for eight weeks with weight attached to the tail. The weight carried during each training session was initially 50% of body weight and progressively increased by 10% per session. The rats in DT were detained for 20 weeks followed by eight weeks strength training. The rats in the both TR and RT groups underwent eight weeks training. DT was age matched new training group while RT was retraining group after 20 weeks of detraining. Soleus, gastrocnemius, tibialis anterior, and flexor hallucis longus (FHL) muscles were harvested in order to measure the weight, and in situ contractile properties of FHL were measured including specific twitch tension (Spt) and specific tetanic tension (Spo). TR showed significant increase in muscle mass compared to CON (P<0.05). DT and RT showed significant increase in muscle mass when compared to all other groups (P<0.05). There was no statistical difference in Spt and Spo among the groups. The present study showed that previous strength training facilitates retraining-induced muscle hypertrophy following long-term cessation of exercise.

Severe Obesity Shifts Metabolic Thresholds but Does Not Attenuate Aerobic Training Adaptations in Zucker Rats.

Severe obesity affects metabolism with potential to influence the lactate and glycemic response to different exercise intensities in untrained and trained rats. Here we evaluated metabolic thresholds and maximal aerobic capacity in rats with severe obesity and lean counterparts at pre- and post-training. Zucker rats (obese: n = 10, lean: n = 10) were submitted to constant treadmill bouts, to determine the maximal lactate steady state, and an incremental treadmill test, to determine the lactate threshold, glycemic threshold and maximal velocity at pre and post 8 weeks of treadmill training. Velocities of the lactate threshold and glycemic threshold agreed with the maximal lactate steady state velocity on most comparisons. The maximal lactate steady state velocity occurred at higher percentage of the maximal velocity in Zucker rats at pre-training than the percentage commonly reported and used for training prescription for other rat strains (i.e., 60%) (obese = 78 ± 9% and lean = 68 ± 5%, P < 0.05 vs. 60%). The maximal lactate steady state velocity and maximal velocity were lower in the obese group at pre-training (P < 0.05 vs. lean), increased in both groups at post-training (P < 0.05 vs. pre), but were still lower in the obese group at post-training (P < 0.05 vs. lean). Training-induced increase in maximal lactate steady state, lactate threshold and glycemic threshold velocities was similar between groups (P > 0.05), whereas increase in maximal velocity was greater in the obese group (P < 0.05 vs. lean). In conclusion, lactate threshold, glycemic threshold and maximal lactate steady state occurred at similar exercise intensity in Zucker rats at pre- and post-training. Severe obesity shifted metabolic thresholds to higher exercise intensity at pre-training, but did not attenuate submaximal and maximal aerobic training adaptations.

Continuous Aerobic Training in Individualized Intensity Avoids Spontaneous Physical Activity Decline and Improves MCT1 Expression in Oxidative Muscle of Swimming Rats.

Although aerobic training has been shown to affect the lactate transport of skeletal muscle, there is no information concerning the effect of continuous aerobic training on spontaneous physical activity (SPA). Because every movement in daily life (i.e., SPA) is generated by skeletal muscle, we think that it is possible that an improvement of SPA could affect the physiological properties of muscle with regard to lactate transport. The aim of this study was to evaluate the effect of 12 weeks of continuous aerobic training in individualized intensity on SPA of rats and their gene expressions of monocarboxylate transporters (MCT) 1 and 4 in soleus (oxidative) and white gastrocnemius (glycolytic) muscles. We also analyzed the effect of continuous aerobic training on aerobic and anaerobic parameters using the lactate minimum test (LMT). Sixty-day-old rats were randomly divided into three groups: a baseline group in which rats were evaluated prior to initiation of the study; a control group (Co) in which rats were kept without any treatment during 12 weeks; and a chronic exercise group (Tr) in which rats swam for 40 min/day, 5 days/week at 80% of anaerobic threshold during 12 weeks. After the experimental period, SPA of rats was measured using a gravimetric method. Rats had their expression of MCTs determined by RT-PCR analysis. In essence, aerobic training is effective in maintaining SPA, but did not prevent the decline of aerobic capacity and anaerobic performance, leading us to propose that the decline of SPA is not fully attributed to a deterioration of physical properties. Changes in SPA were concomitant with changes in MCT1 expression in the soleus muscle of trained rats, suggestive of an additional adaptive response toward increased lactate clearance. This result is in line with our observation showing a better equilibrium on lactate production-remotion during the continuous exercise (LMT). We propose an approach to combat the decline of SPA of rats in their home cages. This new finding is worth for scientists who work with animal models to study the protective effects of exercise.

Training differentially regulates elastin level and proteolysis in skeletal and heart muscles and aorta in healthy rats.

ABSTRACTExercise induces changes in muscle fibers and the extracellular matrix that may depend on elastin content and the activity of proteolytic enzymes. We investigated the influence of endurance training on the gene expression and protein content and/or activity of elastin, elastase, cathepsin K, and plasmin in skeletal and heart muscles and in the aorta. Healthy rats were randomly divided into untrained (n=10) and trained (n=10; 6 weeks of endurance training with increasing load) groups. Gene expression was evaluated via qRT-PCR. Elastin content was measured via enzyme-linked immunosorbent assay and enzyme activity was measured fluorometrically. Elastin content was significantly higher in skeletal (P=0.0014) and heart muscle (P=0.000022) from trained rats versus untrained rats, but not in the aorta. Although mRNA levels in skeletal muscle did not differ between groups, the activities of elastase (P=0.0434), cathepsin K (P=0.0343) and plasmin (P=0.000046) were higher in trained rats. The levels of cathepsin K (P=0.0288) and plasminogen (P=0.0005) mRNA were higher in heart muscle from trained rats, but enzyme activity was not. Enzyme activity in the aorta did not differ between groups. Increased elastin content in muscles may result in better adaption to exercise, as may remodeling of the extracellular matrix in skeletal muscle.

Novel method for functional brain imaging in awake minimally restrained rats.

Functional magnetic resonance imaging (fMRI) in rodents holds great promise for advancing our knowledge about human brain function. However, the use of anesthetics to immobilize rodents during fMRI experiments has restricted the type of questions that can be addressed using this technique. Here we describe an innovative procedure to train rats to be constrained without the need of any anesthesia during the whole procedure. We show that with 8-10 days of acclimation rats can be conscious and remain still during fMRI experiments under minimal stress. In addition, we provide fMRI results of conscious rodents in a variety of commonly used fMRI experimental paradigms, and we demonstrate the improved quality of these scans by comparing results when the same rodents were scanned under anesthesia. We confirm that the awake scanning procedure permits an improved evaluation of brain networks and brain response to external stimuli with minimal movement artifact. The present study further advances the field of fMRI in awake rodents, which provide more direct, forward and reverse, translational opportunities regarding brain functional correspondences between human and rodent research.

Adipose tissue depot specific differences of PLIN protein content in endurance trained rats

ABSTRACTAdipose tissue is classified as either white (WAT) or brown (BAT) and differs not only by anatomical location but also in function. WAT is the main source of stored energy and releases fatty acids in times of energy demand, whereas BAT plays a role in regulating non-shivering thermogenesis and oxidizes fatty acids released from the lipid droplet. The PLIN family of proteins has recently emerged as being integral in the regulation of fatty acid storage and release in adipose tissue. Previous work has demonstrated that PLIN protein content varies among adipose tissue depots, however an examination of endurance training-induced depot specific changes in PLIN protein expression has yet to be done. Male Sprague-dawley rats (n = 10) underwent 8-weeks of progressive treadmill training (18–25 m/min for 30–60 min at 10% incline) or remained sedentary as control. Following training, under isoflurane induced anesthesia epidydmal (eWAT), inguinal subcutaneous (iWAT) and intrascapular brown adipose tissue (BAT) was excised, and plasma was collected. Endurance training resulted in an increase in BAT PLIN5 and iWAT PLIN3 content, while there was no difference in PLIN protein content in endurance trained eWAT. Interestingly, endurance training resulted in a robust increase in ATGL and CGI-58 in eWAT alone. Together these results suggest the potential of a depot specific function of PLIN3 and PLIN5 in adipose tissue in response to endurance training.

Influência da exposição à fumaça de cigarro e do treinamento físico no apetite e desenvolvimento corporal em ratos

The tobacco has the potential to cause changes in the hormonal system, appetite and therefore food intake. In turn, physical training increases metabolic demand, exerts a substantial effect on the energy balance. This study aimed to verify the influence of smoking and physical training in appetite and the development of body weight in rats. Rats Wistar were used (n=40, between 200g and 250g) rats were distributed into four groups: control (C); Trained control (TC); Exposure (E); Trained / exposure (TE). Exposure to cigarette smoke (ECS) and training (swimming) lasted 15 weeks. The animals were weighed weekly and food intake weighed daily. Analyzed with two-way ANOVA and was adopted a significance level of 5%. The ECS intake in rats was lower compared to the non ECS (p=0.001). The trained rats had lower values in intake compared to untrained (p=0.044). The statistical interaction between factors (smoking and swimming) interfered with the intake (p=0.013). The growth curves showed lower body weight in the groups ECS. Was no statistical interaction between smoking and factors swimming to body weight (p=0.046). Statistical difference with higher values for the weights of the heart, lung, and tibia in group no ECS, compared to rats ECS. We conclude that ECS inhibits appetite and promotes loss in body development. And, physical training has chronically negative influence on energy balance, with reduction in weight gain. However, it does not interfere with body development, and beneficial unlike exposure to cigarette smoke.

Resting state functional connectivity data supports detection of cognition in the rodent brain.

Learning is a process which induces plastic changes in the synapses and connections across different regions of the brain. It is hypothesized that these new connections can be tracked with resting state functional connectivity MRI. While most of the evidence of learning-induced plasticity arises from previous human data, data from sedated rats that had undergone training for either 1 day or 5 days in a Morris Watermaze is presented. Seed points were taken from the somatosensory and visual cortices, and the hippocampal CA3 to detect connectivity changes. The data demonstrates that 5-day trained rats showed increased correlations between the hippocampal CA3 and thalamus, septum and cingulate cortex, compared to swim control or naïve animals. Seven days after the training, persistent but reorganized networks toward the cortex were observed. Data from the 1-day trained rats, on the contrary, showed connectivity similar to the swim control and less persistent. The connectivity in several regions was highly correlated with the behavioral performance in these animals. The data demonstrates that longitudinal changes following learning-induced plasticity can be detected and tracked with resting state connectivity.