Trained Rats Research Articles

Neural representation of cost-benefit selections in medial prefrontal cortex of rats.

Decision making refers to the process that subjects use to choose between competing courses of action based on the expected costs and benefits of their consequences. However, few studies have addressed the neuronal mechanisms behind the processes of how costs and benefits influence decision making. Here we investigated the neuronal representation of costs and benefits towards a goal-directed action under a differential reward schedule by training rats to perform a "Do more, get more" (DM-GM) task utilizing a nosepoke operandum, where longer nosepoke durations resulted in correspondingly larger rewards. Our results showed that the cost a rat pays can be expected from the activity of neurons located in the medial prefrontal cortex (mPFC). These findings indicate that mPFC activity is predictive of the subjects' costs and benefits, providing mechanistic insights on this mental calculation.

Interactions between medial prefrontal cortex and dorsomedial striatum are necessary for odor span capacity in rats: role of GluN2B-containing NMDA receptors.

Working memory is involved in the maintenance and manipulation of information essential for complex cognition. While the neural substrates underlying working memory capacity have been studied in humans, considerably less is known about the circuitry mediating working memory capacity in rodents. Therefore, the present experiments tested the involvement of medial prefrontal cortex (mPFC) and dorsal striatum (STR) in the odor span task (OST), a task proposed to assay working memory capacity in rodents. Initially, Long Evans rats were trained to dig in scented sand for food following a serial delayed nonmatching-to-sample rule. Temporary inactivation of dorsomedial (dm) STR significantly reduced span in well trained rats. Inactivation of mPFC or contralateral disconnection of the mPFC and dmSTR also reduced span. Infusing the GluN2B-containing NMDA receptor antagonist Ro 25-6981 into mPFC did not affect span; however, span was significantly reduced following bilateral Ro 25-6981 infusions into dmSTR or contralateral disconnection of mPFC (inactivation) and dmSTR (Ro 25-6981). These results suggest that span capacity in rats depends on GluN2B-containing NMDA receptor-dependent interactions between the mPFC and the dmSTR. Therefore, interventions targeting this circuit may improve the working memory capacity impairments in patients with schizophrenia, Alzheimer's disease, and Parkinson's disease.

Novel spatiotemporal analysis of gait changes in body weight supported treadmill trained rats following cervical spinal cord injury

BackgroundCommon gait measures such as stride length, cycle time, and step height are not independent variables, but different aspects of the same multidimensional step. This complicates comparisons between experimental groups. Here we present a novel multidimensional gait analysis method and use this method to assess the ability of body weight supported treadmill training (BWSTT) to improve rodent stepping after spinal cord injury (SCI).MethodsIn lieu of reducing a step to a collection of gait measures and comparing the means of several of these, we developed a multidimensional analysis technique that compares the step as a whole. While in a passive robotic gait training device, the pre-injury hindlimb stepping of 108 rats was recorded while they walked in a quadrupedal posture at 8 cm/s. Following a C4/5 over-hemisection spinal cord injury the weekly changes in stepping were tracked for 17 untrained and 10 BWSTT animals for 7 weeks. The performance of trained rats was recorded during training with BWS, as well as at the end of the training week without BWS. An additional six uninjured rats were trained for 5 weeks.ResultsOur novel multidimensional analysis shows that stepping is asymmetrically altered 1 week after SCI. The differences in stepping change over the following weeks, with the less impaired left hindlimb deviating further away from pre-injury than the more impaired right hindlimb. Uninjured rats do not significantly alter their stepping over 5 weeks. BWSTT improves the stepping of the right hindlimb, but only when the BWS is active. If the BWS is not present, the performance of trained animals is worse than untrained rats. The left hindlimb performance of BWSTT rats is worse than untrained rats, during both training sessions and weekly assessments.ConclusionsWe feel that our novel multidimensional analysis is a more appropriate method to address the inter-dependencies of gait measures. Untrained rats exhibit both initial impairments as well as the development of compensatory techniques. BWSTT does not improve this spontaneous recovery, but exacerbates it, particularly in the less impaired left hindlimb.

АДАПТАЦИЯ НАСОСНОЙ ФУНКЦИИ СЕРДЦА К МЫШЕЧНОЙ ДЕЯТЕЛЬНОСТИ

Абзалов Рустем Ринатович, кандидат биологических наук, доцент кафедры теории и методики физической культуры, спорта и лечебной физической культуры, Казанский (Приволжский) федеральный университет. 420008, Республика Татарстан, г. Казань, ул. Кремлевская, 18. E-mail: 2902207@mail.ru, ORCID: 0000-0003-4940-1502. Абзалов Наиль Ильясович, доктор биологических наук, доцент, заведующий кафедрой теории и методики физической культуры, спорта и лечебной физической культуры, Казанский (Приволжский) федеральный университет. 420008, Республика Татарстан, г. Казань, ул. Кремлевская, 18. E-mail: nailabzalov@mail.ru, ORCID: 0000-0002-8428-2724. Абзалов Ринат Абзалович, доктор биологических наук, профессор, профессор кафедры теории и методики физической культуры, спорта и лечебной физической культуры, Казанский (Приволжский) федеральный университет. 420008, Республика Татарстан, г. Казань, ул. Кремлевская, 18. E-mail: abzalov2004@mail.ru, ORCID: 0000-0003-1422-3742. Гуляков Андрей Анатольевич, старший преподаватель кафедры теории и методики физической культуры, спорта и лечебной физической культуры, Казанский (Приволжский) федеральный университет. 420008, Республика Татарстан, г. Казань, ул. Кремлевская, 18. E-mail: aguliakov@gmail.com, ORCID: 0000-0002-3010-3946. R.R. Abzalov, 2902207@mail.ru, ORCID: 0000-0003-4940-1502, N.I. Abzalov, nailabzalov@mail.ru, ORCID: 0000-0002-8428-2724, R.A. Abzalov, abzalov2004@mail.ru, ORCID: 0000-0003-1422-3742, A.A. Gulyakov, aguliakov@gmail.com, O ORCID: 0000-0002-3010-3946 Kazan (Volga region) Federal University, Kazan, Russian Federation

A Mechanism Underlying Preventive Effect of High-Intensity Training on Colon Cancer.

We examined effects of high-intensity training on chemically induced aberrant crypt foci (ACF) in rat colon. We also investigated mechanisms that may underlie the results obtained, with a focus on secreted protein acidic and rich in cysteine (SPARC), which has been proposed as an exercise-related factor of colon cancer prevention. After an administration of 1,2-dimethylhydrazine, F344 rats executed high-intensity intermittent swimming training (HIIST) (twelve 20-s swimming with a weight [16% body weight] with 10-s pauses between the bouts) 5 d·wk for 4 wk. The acute and chronic effects of the HIIST on SPARC were evaluated in rats. We evaluated the in vitro and in vivo effects of 5' AMP-activated protein kinase (AMPK) activator on SPARC in rat serum and epitrochlearis muscle. In human subjects, we determined serum SPARC after exhaustive bicycling consisting of six to seven bouts of exercise at 170% V˙O2max with 10-s rests between the bouts (high-intensity intermittent bicycling [HIIB]). The SPARC mRNA in human vastus lateralis was measured before and after the HIIB for 4 d·wk for 6 wk (HIIB-training [HIIBT]). The numbers of ACF were lower in the HIIST (47 ± 22) compared with the control (122 ± 47) rats (P < 0.05). SPARC in epitrochlearis and serum after HIIS of the trained rat was higher than that in the control resting rats. In vitro and vivo AMPK stimulation increased mRNA and SPARC protein in rat epitrochlearis, respectively. The human serum SPARC after the HIIB was elevated. SPARC mRNA in human muscle was elevated after the HIIBT. The results demonstrated that HIIST inhibits 1,2-dimethylhydrazine-induced colon ACF development. This effect may be explained by SPARC induction by the exercise intensity-related factor AMPK, potentially explaining the preventive effects of high-intensity intermittent exercise training against colon cancer.

Efecto de un protocolo de ejercicio por cuatro semanas sobre el peso corporal y la glucemia en rata Wistar

Durante el ejercicio, los requerimientos de glucosa por los tejidos se incrementan, particularmente en el músculo esquelético; durante el ejercicio de intensidad moderada (60-75% VO2máx); el incremento de glucosa es debido a un aumento en la relación glucagon venoso-insulina (Engler 2006). En el presente trabajo se determinó el efecto del ejercicio de resistencia aeróbica durante cuatro semanas sobre el peso corporal y los niveles de glucosa sanguínea en ratas Wistar. Los animales recibieron entrenamiento en una banda sinfín (Modular Enclosed Treadmill; Columbus Instrument, Columbus, OH, USA), cero grados de inclinación, con incorporación de dispositivo eléctrico de 10 mV. El protocolo de marcha se aplicó en sesiones de 30 min/día, a una velocidad de 10 m/min con una frecuencia de 5 veces/semana durante 4 semanas. Se midió el peso corporal y la glucosa sanguínea. Se determinó la Curva de Tolerancia Oral a la Glucosa (CTOG) en sangre en ayuno de 12 horas al inicio y al fin de cuatro semanas de ejercicio. La diferencia entre los grupos se analizó mediante la prueba estadística t de Student para comparación de medias, considerando una p≤0.05 como significativa. Después de cuatro semanas de entrenamiento, los grupos no mostraron diferencias significativas en el peso corporal 262.0±31.78 g al inicio y 292.01±35.62 g al final en el grupo control (p&gt;0.05) vs. 282.75±25.91 g al inicio y 301.47±31.38 al final en el grupo de ratas entrenadas (p&gt;0.05). Asimismo, los niveles de glucosa sanguínea antes y después del protocolo de ejercicio no se modificaron significativamente entre los grupos de estudio, siendo en el grupo control de 73.5±3.8 g/dL al inicio y 83.5±2.38 g/dL después de las 4 semanas de estudio; mientras que en el grupo experimental el nivel de glucosa sanguíneo disminuyó de 91.0±7.43 g/dL al inicio a 85.7±7.0 g/dL al final de las 4 semanas del protocolo de entrenamiento; sin embargo, esta diferencia no fue significativa entre los grupos (p&gt;0.05). La CTOG antes y después del protocolo de ejercicio tendió a ser similar en ambos grupos de estudio.

Resistance training regulates gene expression of molecules associated with intramyocellular lipids, glucose signaling and fiber size in old rats

Sarcopenia is a complex multifactorial process, some of which involves fat infiltration. Intramyocellular lipid (IMCL) accumulation is postulated to play a role on sarcopenia during aging, which is believed to be due alterations in glucose homeostasis in the skeletal muscle. Sarcopenia, along with intramuscular lipids, is associated with physical inactivity. Resistance training (RT) has been indicated to minimize the age-induced muscle skeletal adaptations. Thus, we aimed to investigate the effects of RT on mRNA levels of regulatory components related to intramyocellular lipid, glucose metabolism and fiber size in soleus and gastrocnemius muscles of aged rats. Old male rats were submitted to RT (ladder climbing, progressive load, 3 times a week for 12 weeks). Age-induced accumulation of IMCL was attenuated by RT, which was linked to a PPARy-mediated mechanism, concomitant to enhanced regulatory components of glucose homeostasis (GLUT-4, G6PDH, Hk-2 and Gly-Syn-1). These responses were also linked to decreased catabolic (TNF-α, TWEAK/Fn14 axis; FOXO-1, Atrogin-1 and MuRF1; Myostatin) and increased anabolic intracellular pathways (IGF-1-mTOR-p70S6sk-1 axis; MyoD) in muscles of trained aged rats. Our results point out the importance of RT on modulation of gene expression of intracellular regulators related to age-induced morphological and metabolic adaptations in skeletal muscle.

The influence of heavy physical effort on proteolytic adaptations in skeletal and heart muscle and aorta in rats.

Physical effort can elicit differential adaptive changes in the tissues of trained versus untrained rats. Proteolytic activity in the extracellular matrix could be engaged in such adaptation due to its influence on the elasticity of tissues. The effects were investigated of a single physical effort on the activity of elastase, cathepsin K, and plasmin in the skeletal muscles, heart muscles, and aortas of untrained (UT, n=30) and trained (T, n=30) rats. T rats underwent 6 weeks of endurance training. After the last training session, T and UT rats were divided randomly into 3 subgroups. Ten rats from each group (Tpre, n=10) and (UTpre, n=10) were sacrificed. The other 20 rats from each group performed 60 min. of aerobic exercise and were sacrificed immediately post exercise (T0h, n=10; UT0h, n=10) or 3h later (T3h, n=10; UT3h, n=10). Enzyme activity was measured fluorometrically. Cathepsin K and plasmin activity increased in the soleus muscles of UT0h versus UTpre, plasmin activity increased also in UT3h versus UTpre. Elastase, cathepsin K and plasmin activity increased in the heart muscles of T0h and T3h versus Tpre. No aortic differences were observed. Thus, a single bout of physical effort elicited different responses in tissues of T versus UT rats. Increased proteolytic enzyme levels in muscles could influence tissue remodeling. Unchanged aortic cathepsin K levels may help prevent aortic remodeling and neointima formation.

Muscular glucose metabolism in middle-age trained rats

Aging decreases the normal organism physiological functions. On the other hand, physical exercise shows health benefits, but little information is known about physical deconditioning at aging. The aim of the present study was to analyze the glucose muscle metabolism in middle-age Wistar rats in response to conditioning and physical deconditioning. The study included three groups: Control (C)—not performed physical training; Trained (T)—performed physical training from 4 to 12 months—swimming exercise for 1 h per day, 5 days per week at 80% of maximal lactate stead state—MLSS; Detrained (D)—performed to physical training from 4 to 8 months and assessed at 12 months (D). Physical training at submaximal intensities induced decreases in body weight (C 588 ± 71, T 515 ± 72, D 576 ± 62 g), and the weight of mesenteric adipose tissue (C 4399 ± 643, T 3007 ± 811, D 4085 ± 540 mg/g), and increases in exercise workload in MLSS intensity (C 4.6 ± 0.4, T 5.8 ± 1.3, D 5.3 ± 0.4% body weight), glucose tolerance (C 12314 ± 1122, T 8428 ± 853, D 9433 ± 1200 mg/dL 120 min), glycogen deposits (C 0.48 ± 0.07, T 0.66 ± 0.18, D 0.46 ± 0.10 mg/100 mg) and glucose uptake by skeletal muscle (C 1.96 ± 0.54, T 3.28 ± 0.53, D 2.55 ± 0.35 μmol/g/h) in trained animals. Additionally, the improvement in exercise load in MLSS, glucose tolerance and glucose uptake was maintained after physical detraining. In summary, the physical training promotes alterations in body weight, fat tissue, aerobic capacity and muscular glucose metabolism in middle-age rats. However, only the aerobic capacity and muscular glucose metabolism were maintained after detraining.

Strategies of adaptation of small arteries in diaphragm and gastrocnemius muscle to aerobic exercise training

Aerobic exercise training is associated with adaptive changes in skeletal muscles and their vascular bed; such changes in individual muscles may vary depending on their characteristics and recruitment. This study was aimed at comparing the effects of eight-week treadmill training on the locomotor and respiratory muscles in rats. The training course increased the aerobic performance in rats, which was evidenced by an increase in maximum O2 consumption and a decrease in the blood lactate concentration in ramp test. The succinate dehydrogenase activity was increased in the red portion of the gastrocnemius muscle, but not in the diaphragm of trained rats. Arterial segments were isolated from feed arteries and studied by wire myography. The relaxation in response to acetylcholine in gastrocnemius arteries in trained animals was higher as compared with controls (due to higher NO production), while contractile responses to noradrenaline (in the presence of propranolol) were not changed. On the contrary, the endothelial function of diaphragm arteries was not affected by training, but contractile responses to activation of α-adrenoceptors were markedly increased. Thus, aerobic training may increase the blood supply rate to both locomotor and respiratory muscles, but the underlying regulatory mechanisms are different. The results obtained allow us to reveal the physiological mechanisms that determine the physical performance of the body under conditions of compromised functioning of the respiratory system.

The effect of endurance training on dynein motor protein expression in Wistar male rats sciatic nerves with diabetic neuropathy

Introduction: Most neurodegenerative diseases are associated with the disruption of axonal transport and this might also be related to diabetes-associated disorders affecting the nervous system. Cytoplasmic dynein is a very important motor driving the movement of a wide range of cargoes toward the minus ends of microtubules. The effects of endurance training on dynein motor protein expression in Wistar male rats sciatic nerves with diabetic neuropathy were investigated. Methods: Twenty one male Wistar rats were divided into three groups: diabetic control (DC: n=7), diabetic trained (DT: n=7) and Healthy control (HC: n=7). Two weeks post STZ injection (45 mg/kg, i.p.), rats were subjected to treadmill exercise for 5 days a week for over 6 weeks. Levels of mRNA and protein content were determined by Real time-PCR and ELISA. Results: The blood glucose levels and dynein mRNA in both sensory and motor parts and dynein content in sciatic nerves were increased by diabetes (P≤0.05). Furthermore, exercise training modulated the dynein mRNA and dynein content to normal levels in diabetic trained rats (P≤0.05). Moreover, exercise training reduced blood glucose levels in the DT rats (P≤0.05). Conclusion: The results of the present study confirm that dynein expresses up-regulation in STZ-induced diabetic rats. Increase in the amount of dynein expression can be a compensatory response in the lower trophic support and burden imposed on autophagy system. These alterations suggest that retrograde axonal transport may be impaired in diabetic rats. In addition, endurance training as a non-pharmacotherapy strategy can modulate these alterations.

Role of vitamin A oral supplementation on oxidative stress and inflammatory response in the liver of trained rats.

The use of dietary supplements to enhance the benefit of exercise training is a common practice. The liver is the organ where all substances are metabolized, and certain supplements have been associated with liver injury. Vitamin A (VA), a liposoluble vitamin stored in the liver, is commonly used as an antioxidant supplement. Here, we evaluated the effect of chronic VA supplementation on oxidative damage and stress parameters in trained rats. Animals were divided into the following groups: sedentary (SE), sedentary/VA (SE+VA), exercise training (ET), and exercise training/VA (ET+VA). During 8 weeks, animals were subjected to swimming (0%, 2%, 4%, 6% body weight) for 5 days/week and a VA daily intake of 450 retinol equivalents/day. Parameters were evaluated by enzymatic activity analysis, ELISA, and Western blotting. VA caused liver lipid peroxidation and protein damage in exercised rats and inhibited the increase in HSP70 expression acquired with exercise alone. The ET group showed higher levels of antioxidant enzyme activity, and VA inhibited this adaptation. Expression of the pro-inflammatory cytokines, interleukin (IL)-1β, and tumor necrosis factor-α was reduced in the ET+VA group, while the anti-inflammatory cytokine, IL-10, was increased. Western blotting showed that both exercised groups had lower levels of the receptor for advanced glycation end products, suggesting that VA did not affect this receptor. Our study demonstrated that, although VA caused oxidative damage, a controlled administration might exert anti-inflammatory effects. Further studies with higher VA doses and longer ET interventions would elucidate more the effects of the supplementation and exercise on liver parameters.

Microsurgical Bypass Training Rat Model, Part 1: Technical Nuances of Exposure of the Aorta and Iliac Arteries.

Animal models using rodents are frequently used for practicing microvascular anastomosis-an essential technique in cerebrovascular surgery. However, safely and efficiently exposing rat's target vessels is technically difficult. Such difficulty may lead to excessive hemorrhage and shorten animal survival. This limits the ability to perform multiple anastomoses on a single animal and may increase the overall training time and costs. We report our model for microsurgical bypass training in rodents in 2 consecutive articles. In part 1, we describe the technical nuances for a safe and efficient exposure of the rat abdominal aorta and common iliac arteries (CIAs) for bypass. Over a 2-year period, 50 Sprague-Dawley rats underwent inhalant anesthesia for practicing microvascular anastomosis on the abdominal aorta and CIAs. Lessons learned regarding the technical nuances of vessel exposure were recorded. Several technical nuances were important for avoiding intraoperative bleeding and preventing animal demise while preparing an adequate length of vessels for bypass. The most relevant technical nuances include (1) generous subcutaneous dissection; (2) use of cotton swabs for the blunt dissection of the retroperitoneal fat; (3) combination of sharp and blunt dissection to isolate the aorta and iliac arteries from the accompanying veins; (4) proper control of the posterior branches of the aorta; and (5) efficient division and mobilization of the left renal pedicle. Applying the aforementioned technical nuances enables safe and efficient preparation of the rat abdominal aorta and CIAs for microvascular anastomosis.

Microsurgical Bypass Training Rat Model: Part 2-Anastomosis Configurations.

Mastery of microsurgical anastomosis is key to achieving good outcomes in cerebrovascular bypass procedures. Animal models (especially rodents) provide an optimal preclinical bypass training platform. However, the existing models for practicing different anastomosis configurations have several limitations. We sought to optimize the use of the rat's abdominal aorta and common iliac arteries (CIA) for practicing the 3 main anastomosis configurations commonly used in cerebrovascular surgery. Thirteen male Sprague-Dawley rats underwent inhalant anesthesia. The abdominal aorta and the CIAs were exposed. The distances between the major branches of the aorta were measured to find the optimal location for an end-to-end anastomosis. Also, the feasibility of performing side-to-side and end-to-side anastomoses between the CIAs was assessed. All bypass configurations could be performed between the left renal artery and the CIA bifurcation. The longest segments of the aorta without major branches were 1) between the left renal and left iliolumbar arteries (16.9 mm ± 4.6), and 2) between the right iliolumbar artery and the aortic bifurcation (9.7 mm ± 4.7). The CIAs could be juxtaposed for an average length of 7.6 mm ± 1.3, for a side-to-side anastomosis. The left CIA could be successfully reimplanted on to the right CIA at an average distance of 9.1 mm ± 1.6 from the aortic bifurcation. Our results show that rat's abdominal aorta and CIAs may be effectively used for all the anastomosis configurations used in cerebral revascularization procedures. We also provide technical nuances and anatomic descriptions to plan for practicing each bypass configuration.

Positive impacts of early auditory training on cortical processing at an older age

Progressive negative behavioral changes in normal aging are paralleled by a complex series of physical and functional declines expressed in the cerebral cortex. In studies conducted in the auditory domain, these degrading physical and functional cortical changes have been shown to be broadly reversed by intensive progressive training that improves the spectral and temporal resolution of acoustic inputs and suppresses behavioral distractors. Here we found older rats that were intensively trained on an attentionally demanding modulation-rate recognition task in young adulthood substantially retained training-driven improvements in temporal rate discrimination abilities over a subsequent 18-mo epoch-that is, forward into their older age. In parallel, this young-adult auditory training enduringly enhanced temporal and spectral information processing in their primary auditory cortices (A1). Substantially greater numbers of parvalbumin- and somatostatin-labeled inhibitory neurons (closer to the numbers recorded in young vigorous adults) were recorded in the A1 and hippocampus in old trained versus untrained age-matched rats. These results show that a simple form of training in young adulthood in this rat model enduringly delays the otherwise expected deterioration of the physical status and functional operations of the auditory nervous system, with evident training impacts generalized to the hippocampus.

Prefrontal Dopamine D1 and D2 Receptors Regulate Dissociable Aspects of Decision Making via Distinct Ventral Striatal and Amygdalar Circuits.

Mesocortical dopamine (DA) regulates a variety of cognitive functions via actions on D1 and/or D2 receptors. For example, risk/reward decision making is modulated differentially by these two receptors within the prefrontal cortex (PFC), with D2 receptors enabling flexible decision making and D1 receptors promoting persistence in choice biases. However, it is unclear how DA mediates opposing patterns of behavior by acting on different receptors within the same terminal region. We explored the possibility that DA may act on separate networks of PFC neurons that are modulated by D1 or D2 receptors and in turn interface with divergent downstream structures such as the basolateral amygdala (BLA) or nucleus accumbens (NAc). Decision making was assessed using a probabilistic discounting task in which well trained male rats chose between small/certain or large/risky rewards, with the odds of obtaining the larger reward changing systematically within a session. Selective disruption of D1 or D2 modulation of separate PFC output pathways was achieved using unilateral intra-PFC infusions of DA antagonists combined with contralateral inactivation of the BLA or NAc. Disrupting D2 (but not D1) modulation of PFC→BLA circuitry impaired adjustments in decision biases in response to changes in reward probabilities. In contrast, disrupting D1 modulation of PFC→NAc networks reduced risky choice, attenuating reward sensitivity and increasing sensitivity to reward omissions. These findings reveal that mesocortical DA can facilitate dissociable components of reward seeking and action selection by acting on different functional networks of PFC neurons that can be distinguished by the subcortical projection targets with which they interface.SIGNIFICANCE STATEMENT Prefrontal cortical dopamine regulates a variety of executive functions governed by the frontal lobes via actions on D1 and D2 receptors. These receptors can in some instances mediate different patterns of behavior, but the mechanisms underlying these dissociable actions are unclear. Using a selective disconnection approach, we reveal that D1 and D2 receptors can facilitate diverse aspects of decision making by acting on separate networks of prefrontal neurons that interface with distinct striatal or amygdalar targets. These findings reveal an additional level of complexity in how mesocortical DA regulates different forms of cognition via actions on different receptors, highlighting how it may act upon distinct cortical microcircuits to drive different patterns of behavior.

Influence of protein deficient diet, vitamin B[sub]2[/sub] supplementation and physical training on serum composition of polyunsaturated fatty acids (PUFAs) in rats.

[b]Introduction[/b]. Prolonged shortages of protein in the diet significantly alter the composition and content of polyunsaturated fatty acids (PUFA) in tissues and body fluids. One of nutritional factors which may reduce negative effects of protein malnutrition might be vitamin B[sub]2[/sub] due to its influence on lipids metabolism. [b]Objective. [/b]The aim of the study was to investigate the influence of low protein (LP) diet enriched with vitamin B[sub]2[/sub] on the content and composition of PUFA in the blood serum of rats treated with dosed physical exercise. [b]Materials and method. [/b]The experiment was carried out for 3 months on 72 growing male Wistar rats divided into 5 groups. Animals were fed ad libitum on a diet with an energy value of 350 kcal/100 g, in which 4.5% of the energy was provided by protein. In the control diet, 20% of the energy was provided by protein. Two groups were fed the diet enriched with vitamin B2. The two groups of tested animals were trained for 5 days a week. [b]Results.[/b] LP diet caused a decrease in α-linolenic acid (ALA) after 30 days, and a decrease in docosahexaenoic acid (DHA) after 60 days of experiment, compared with rats fed the control diet. After 60 and 90 days of the experiment, a significant decrease was noted in arachidonic acid (AA) in serum of trained rats, compared with sedentary rats fed the LP diet. Physical activity increased LA (mainly on day 30), EPA (on day 90) and reduced AA content (on day 90) in serum of rats fed the LP diet. B2 supplementation in the trained LP group did not change the EPA and AA dependence; however, there was a decrease in LA content in comparison to the non-supplemented trained group. [b]Conclusions. [/b] Results of this study suggest that all investigated factors (protein deficiency, physical exercise and supplementation of vitamin B2) have significant impact on PUFA composition of serum in rats.

Effects of endurance training and herb supplementation on tissue nesfatin-1/nucleobindin-2 and ghrelin mRNA expression

This study investigated the effects of aerobic training and extract of Pistacia-atlantica (Baneh) as a plant with rich fatty acids, on tissue nesfatin-1/nucleobindin-2 and ghrelin gene expression, plasma high- and low-density lipoprotein, tissue/plasma total cholesterol and triglyceride concentrations in female rats. 20 Wistar rats were randomly assigned to saline-control, saline-training, Baneh-control, and Baneh-training groups. The training groups were given a specific exercise on a motor-driven treadmill for 8 weeks. Nesfatin-1/nucleobindin-2 and ghrelin mRNA expressions were detected by Real-time PCR method. According to the results, the trained rats had higher nesfatin-1 mRNA expressions in liver and visceral fat and liver estradiol concentration but their liver ghrelin mRNA expressions were lower compared to the control rats. Baneh-treated rats had lower nesfatin-1 mRNA expressions in liver and visceral fat and plasma HDL-C concentration, but their plasma estradiol concentrations were significantly higher. Moreover, liver estradiol concentration and liver ghrelin mRNA expression were negatively correlated, whereas the correlation between plasma estradiol and HDL-C concentrations and nesfatin-1 mRNA expression in visceral fat was significantly positive. Generally, exercise and a high-fat diet induced changes in liver ghrelin, nesfatin-1 mRNA expression, liver estradiol level, and nesfatin-1 in visceral fat, nesfatin-1 expression in liver and visceral fat, liver glucose, plasma HDL-C, and estradiol.

Cardiac hypertrophy and IGF-1 response to testosterone propionate treatment in trained male rats

AbstractObjectiveSeveral studies have suggested that testosterone exerts a growth-promoting effect in the heart. Limited data are available regarding interactions between possible endocrine/paracrine effects in response to exercise training. Therefore, we examined supraphysiological testosterone-induced heart hypertrophy and cardiac insulin-like growth factor (IGF)-1 content in sedentary and exercise-trained rats.DesignMale Wistar rats (n=33) were randomly allocated to groups with a 6-week endurance training with or without testosterone, and sedentary animals with or without testosterone. The hormone (20 mg/250 g body weight was administrated once a week for six weeks. After six weeks the animals were anesthetized, euthanized and the heart was excised and weighed. The left ventricle was separated for biochemical analyses.ResultsTestosterone-treated animals showed significantly higher cardiac IGF-1 content compared to untreated control and trained groups (p=0.01). The administration of supraphysiological testosterone significantly increased the heart weight to body weight ratio (HW/BW, p&lt;0.01). A significant positive correlation was seen between IGF-1 levels and the HW/BW ratio (p=0.002; r=0.50) and between serum total testosterone levels and HW/BW (p=0.000; r=0.79).ConclusionsThe results demonstrate that increased cardiac IGF-1 content in response to higher serum testosterone might be responsible for heart hypertrophy observed in both sedentary and endurance-trained animals.

Antifatigue effects of troxerutin on exercise endurance capacity, oxidative stress and matrix metalloproteinase-9 levels in trained male rats.

The aim of this study was to investigate effects of troxerutin (TRX) on endurance capacity, oxidative stress and matrix metalloproteinase-9 (MMP-9) levels in trained male rats. Forty male Wistar rats were divided into five groups. The control (Vehicle) and exercise training (5days/week) with vehicle treatment (Exercise), exercise training with TRX treatment at 75 (Ex-TRX75), 150 (Ex-TRX150), and 300mg/kg (Ex-TRX300). The treated groups received TRX by gavage every day while the other groups received water for 30days. On the 30th day, rats were sacrificed immediately after exhaustive swimming test, and some biochemical parameters were measured. Exhaustion swimming time in the Ex-TRX75, Ex-TRX150 and Ex-TRX300 groups significantly increased 1.2-, 1.93- and 2.1-fold compared to the vehicle group, respectively. TRX significantly increased glucose level (P<0.05) and reduced creatine kinase activity (P<0.001) compared to the vehicle and exercise groups. TRX300 significantly reduced alkaline phosphatase and lactate dehydrogenase activities (P<0.05) and blood urea nitrogen (P<0.05) and MMP-9 levels (P<0.05) compared to the vehicle and exercise groups. Additionally, TRX300 and TRX150 significantly increased superoxide dismutase activity compared to the vehicle group (P<0.05). Our results provide experimental evidence in supporting clinical use of TRX as an effective agent against fatigue.