scholarly journals Forced internal desynchrony induces cardiometabolic alterations in adult rats

2019 ◽  
Vol 242 (2) ◽  
pp. 25-36
Author(s):  
Isis Gabrielli Barbieri de Oliveira ◽  
Marcos Divino Ferreira Junior ◽  
Paulo Ricardo Lopes ◽  
Dhiogenes Balsanufo Taveira Campos ◽  
Marcos Luiz Ferreira-Neto ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Metabolic Response ◽  
Hepatic Metabolism ◽  
Control Group ◽  
Dark Cycle ◽  
Adult Rats ◽  
Internal Desynchronization ◽  
Male Wistar Rats ◽  
Experimental Group

Disruptions in circadian rhythms have been associated with several diseases, including cardiovascular and metabolic disorders. Forced internal desynchronization induced by a period of T-cycles of 22 h (T22 protocol) reaches the lower limit of entrainment and dissociates the circadian rhythmicity of the locomotor activity into two components, driven by different outputs from the suprachiasmatic nucleus (SCN). The main goal of this study was to evaluate the cardiovascular and metabolic response in rats submitted to internal desynchronization by T22 protocol. Male Wistar rats were assigned to either a control group subjected to a usual T-cycles of 24 h (12 h–12 h) or an experimental group subjected to the T22 protocol involving a 22-h symmetric light–dark cycle (11 h–11 h). After 8 weeks, rats subjected to the T22 exhibited desynchrony in their locomotor activity. Although plasma glucose and insulin levels were similar in both groups, desynchronized rats demonstrated dyslipidemia, significant hypertrophy of the fasciculate zone of the adrenal gland, low IRB, IRS2, PI3K, AKT, SOD and CAT protein expression and an increased expression of phosphoenolpyruvate carboxykinase in the liver. Furthermore, though they maintained normal baseline heart rates and mean arterial pressure levels, they also presented reduced baroreflex sensitivity. The findings indicate that circadian timing desynchrony following the T22 protocol can induce cardiometabolic disruptions. Early hepatic metabolism dysfunction can trigger other disorders, though additional studies are needed to clarify the causes.

scholarly journals Diazepam attenuates the effects of cocaine on locomotion, 50-kHz ultrasonic vocalizations and phasic dopamine release in the nucleus accumbens of rats

2020 ◽  
Author(s):  
William N. Sanchez ◽  
Jose A. Pochapski ◽  
Leticia F. Jessen ◽  
Marek Ellenberger ◽  
Rainer K. Schwarting ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Nucleus Accumbens ◽  
Dopamine Release ◽  
Ultrasonic Vocalizations ◽  
Control Group ◽  
List Type ◽  
Adult Rats ◽  
Fast Scan Cyclic Voltammetry ◽  
Entire Duration ◽  
Male Wistar Rats

AbstractBackground and PurposeCurrently, no effective drug exists to treat cocaine use disorders, which affect millions of people worldwide. Benzodiazepines are potential therapeutic candidates, as microdialysis and voltammetry studies have shown that they can decrease dopamine release in the nucleus accumbens of rodents. In addition, we have recently shown that diazepam blocks the increase in dopamine release and the affective marker 50-kHz ultrasonic vocalizations (USV) induced by DL-amphetamine in rats.Experimental ApproachHere we tested whether administration of 2.5 mg·kg−1 diazepam (i.p.) in adult male Wistar rats could block the effects of 20 mg·kg−1 cocaine (i.p.) on electrically evoked phasic dopamine release in the nucleus accumbens measured by fast-scan cyclic voltammetry, as well as 50-kHz USV and locomotor activity.Key ResultsCocaine injection increased evoked dopamine release up to 3-fold within 5 min and the increase was significantly higher than baseline for at least 90 min. The injection of diazepam 15 min later attenuated the cocaine effect by nearly 50% and this attenuation was maintained for at least 30 min. Stimulant drugs, natural rewards and reward predictive cues are known to evoke 50-kHz USV in adult rats. In the present study, cocaine increased the number of 50-kHz USV of the flat, step, trill, and mixed kinds by 12-fold. This effect was at maximum 5 min after cocaine injection, decreased with time and lasted at least 40 min. Diazepam significantly blocked this effect for the entire duration of the session. The distance travelled by control rats during a 40-min session of exploration in an open field was at maximum in the first 5 min and decayed progressively until the end of the session. Cocaine-treated rats travelled significantly longer distances when compared to the control group, while diazepam significantly attenuated cocaine-induced locomotion by up to 50%.Conclusions and implicationThese results suggest that the neurochemical, affective, and stimulant effects of cocaine can be mitigated by diazepam.What is already knownDiazepam decreases dopamine release in the rodent nucleus accumbens (NAc) and reduces some effects produced by DL-amphetamine.What this study addsDiazepam attenuated the increase in phasic dopamine release caused by cocaine.Diazepam blocked the effect of cocaine on 50-kHz USV and locomotor activity.Clinical significanceThis study demonstrates that diazepam can block specific effects of cocaine that likely contribute to addiction.

Effect of Strychnine Sulfate on Locomotor Activity

1965 ◽  
Vol 20 (3_suppl) ◽  
pp. 1049-1053 ◽  
Author(s):  
Robert G. Gibby ◽  
Robert G. Gibby ◽  
George B. Kish ◽  
George C. Theologus
Keyword(s):  
Locomotor Activity ◽  
Open Field ◽  
Exploratory Behavior ◽  
Normal Saline ◽  
Behavioral Change ◽  
Wistar Rats ◽  
Spontaneous Locomotor Activity ◽  
Control Group ◽  
Male Wistar Rats ◽  
Experimental Group

The effect of strychnine sulfate upon spontaneous locomotor activity in an open field was determined for 20 naive male Wistar rats. The experimental Ss were injected ip with 1.0 cc/kg of a 01% solution of strychnine sulfate in normal saline and the control Ss received a similar injection of 1.0 cc/kg of normal saline. All Ss were given 2 trials 7 days apart in the open field, with the injections preceding the second trial. The behavioral change from Trial 1 to Trial 2 for the control group was compared with that for the experimental group. Strychnine sulfate significantly reduced spontaneous locomotor activity in rats. A significant correlation was found between scores on the first and second trials of the experimental Ss. It was suggested that the concept of “orienting-exploratory behavior” could account for reduced locomotor activity.

scholarly journals Running wheel training does not change neurogenesis levels or alter working memory tasks in adult rats

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2976 ◽  
Author(s):  
Cesar A. Acevedo-Triana ◽  
Manuel J. Rojas ◽  
Fernando Cardenas P.
Keyword(s):  
Working Memory ◽  
Exercise Program ◽  
Hippocampal Neurogenesis ◽  
Control Group ◽  
Adult Rats ◽  
Preference Index ◽  
Maze Test ◽  
Behavioral Variables ◽  
Male Wistar Rats ◽  
Experimental Group

BackgroundExercise can change cellular structure and connectivity (neurogenesis or synaptogenesis), causing alterations in both behavior and working memory. The aim of this study was to evaluate the effect of exercise on working memory and hippocampal neurogenesis in adult male Wistar rats using a T-maze test.MethodsAn experimental design with two groups was developed: the experimental group (n = 12) was subject to a forced exercise program for five days, whereas the control group (n = 9) stayed in the home cage. Six to eight weeks after training, the rats’ working memory was evaluated in a T-maze test and four choice days were analyzed, taking into account alternation as a working memory indicator. Hippocampal neurogenesis was evaluated by means of immunohistochemistry of BrdU positive cells.ResultsNo differences between groups were found in the behavioral variables (alternation, preference index, time of response, time of trial or feeding), or in the levels of BrdU positive cells.DiscussionResults suggest that although exercise may have effects on brain structure, a construct such as working memory may require more complex changes in networks or connections to demonstrate a change at behavioral level.

scholarly journals The use of Portland cement in the repair of mandibular fractures in rats

2011 ◽  
Vol 26 (6) ◽  
pp. 426-432
Author(s):  
Reginaldo Inojosa Carneiro Campello ◽  
Belmiro Cavalcanti do Egito Vasconcelos ◽  
Gerhilde Callou Sampaio ◽  
Antonio Rolim ◽  
Gabriela Granja Porto
Keyword(s):  
Portland Cement ◽  
Bone Healing ◽  
Soft Tissues ◽  
Lethal Dose ◽  
Mandibular Fracture ◽  
Point Of View ◽  
Control Group ◽  
Mandibular Fractures ◽  
Male Wistar Rats ◽  
Experimental Group

PURPOSE: To evaluate the bone healing of mandibular fractures following the use of Portland cement. METHODS: Thirty-two male Wistar rats were divided into control and experimental groups. In the control group the rats were submitted to a mandibular fracture, which was reduced, and the soft tissues were sutured. In the experimental group the rats had the mandibular fracture reduced and maintained with the Portland cement. The animals were euthanized 7 and 21 days after surgery by injecting a lethal dose of anesthetic. The following variables were studied: weight of the animals, radiographic images, histopathological features and time of surgery. RESULTS: A weight loss was observed in the specimens of both groups at the different times of evaluation, a greater difference in weight before and after surgery being found in the experimental group, which was statistically significant (p <0.05, p = 0.041). From the histological point of view, with a margin of error (5.0%) the only two significant differences (p <0.05) recorded in the variables were "Material deployed" and "Bone resorption" during the evaluations at 7 and 21 days, respectively. CONCLUSION: The Portland cement served to promote bone healing.

scholarly journals A Subpressor Dose of Angiotensin II Elevates Blood Pressure in a Normotensive Rat Model by Oxidative Stress

2015 ◽  
pp. 153-159 ◽  
Author(s):  
M. M. GOVENDER ◽  
A. NADAR
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Angiotensin Ii ◽  
Mrna Expression ◽  
Rat Model ◽  
Wistar Rat ◽  
Control Group ◽  
Sod Activity ◽  
Male Wistar Rats ◽  
Experimental Group

Oxidative stress is an imbalance between free radicals and antioxidants, and is an important etiological factor in the development of hypertension. Recent experimental evidence suggests that subpressor doses of angiotensin II elevate oxidative stress and blood pressure. We aimed to investigate the oxidative stress related mechanism by which a subpressor dose of angiotensin II induces hypertension in a normotensive rat model. Normotensive male Wistar rats were infused with a subpressor dose of angiotensin II for 28 days. The control group was sham operated and infused with saline only. Plasma angiotensin II and H2O2 levels, whole-blood glutathione peroxidase, and AT-1a, Cu/Zn SOD, and p22phox mRNA expression in the aorta was assessed. Systolic and diastolic blood pressures were elevated in the experimental group. There was no change in angiotensin II levels, but a significant increase in AT-1a mRNA expression was found in the experimental group. mRNA expression of p22phox was increased significantly and Cu/Zn SOD decreased significantly in the experimental group. There was no significant change to the H2O2 and GPx levels. Angiotensin II manipulates the free radical-antioxidant balance in the vasculature by selectively increasing O2− production and decreasing SOD activity and causes an oxidative stress induced elevation in blood pressure in the Wistar rat.

Western diet in the perinatal period promotes dysautonomia in the offspring of adult rats

2016 ◽  
Vol 8 (2) ◽  
pp. 216-225 ◽  
Author(s):  
R. Vidal-Santos ◽  
F. N. Macedo ◽  
M. N. S. Santana ◽  
V. U. De Melo ◽  
J. L. de Brito Alves ◽  
...  
Keyword(s):  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Systolic Arterial Pressure ◽  
Perinatal Period ◽  
Western Diet ◽  
Control Group ◽  
Standard Diet ◽  
Adult Rats ◽  
Male Wistar Rats ◽  
The Impact

The present study investigated the impact of a western diet during gestation and lactation on the anthropometry, serum biochemical, blood pressure and cardiovascular autonomic control on the offspring. Male Wistar rats were divided into two groups according to their mother’s diet received: control group (C: 18% calories of lipids) and westernized group (W: 32% calories of lipids). After weaning both groups received standard diet. On the 60th day of life, blood samples were collected for the analysis of fasting glucose and lipidogram. Cardiovascular parameters were measured on the same period. Autonomic nervous system modulation was evaluated by spectrum analysis of heart rate (HR) and systolic arterial pressure (SAP). The W increased glycemia (123±2v. 155±2 mg/dl), low-density lipoprotein (15±1v. 31±2 mg/dl), triglycerides (49±1v. 85±2 mg/dl), total cholesterol (75±2v. 86±2 mg/dl), and decreased high-density lipoprotein (50±4v. 38±3 mg/dl), as well as increased body mass (209±4v. 229±6 g) than C. Furthermore, the W showed higher SAP (130±4v. 157±2 mmHg), HR (357±10v. 428±14 bpm), sympathetic modulation to vessels (2.3±0.56v. 6±0.84 mmHg2) and LF/HF ratio (0.15±0.01v. 0.7±0.2) than C. These findings suggest that a western diet during pregnancy and lactation leads to overweight associated with autonomic misbalance and hypertension in adulthood.

scholarly journals Morphometric evaluation of condylar cartilage of growing rats in response to mandibular retractive forces

2013 ◽  
Vol 18 (4) ◽  
pp. 113-119 ◽  
Author(s):  
Milena Peixoto Nogueira de Sá ◽  
Jacqueline Nelisis Zanoni ◽  
Carlos Luiz Fernandes de Salles ◽  
Fabrício Dias de Souza ◽  
Uhana Seifert Guimarães Suga ◽  
...  
Keyword(s):  
Functional Class ◽  
Control Group ◽  
Class Iii ◽  
Condylar Cartilage ◽  
Time Intervals ◽  
Undifferentiated Cells ◽  
Male Wistar Rats ◽  
Mandibular Retrusion ◽  
Experimental Group ◽  
Morphometric Evaluation

INTRODUCTION: The mandibular condylar surface is made up of four layers, i.e., an external layer composed of dense connective tissue, followed by a layer of undifferentiated cells, hyaline cartilage and bone. Few studies have demonstrated the behavior of the condylar cartilage when the mandible is positioned posteriorly, as in treatments for correcting functional Class III malocclusion. OBJECTIVE: The aim of this study was to assess the morphologic and histological aspects of rat condyles in response to posterior positioning of the mandible. METHODS: Thirty five-week-old male Wistar rats were selected and randomly divided into two groups: A control group (C) and an experimental group (E) which received devices for inducing mandibular retrusion. The animals were euthanized at time intervals of 7, 21 and 30 days after the experiment had began. For histological analysis, total condylar thickness was measured, including the proliferative, hyaline and hypertrophic layers, as well as each layer separately, totaling 30 measurements for each parameter of each animal. RESULTS: The greatest difference in cartilage thickness was observed in 21 days, although different levels were observed in the other periods. Group E showed an increase of 39.46% in the total layer, reflected by increases in the thickness of the hypertrophic (42.24%), hyaline (46.92%) and proliferative (17.70%) layers. CONCLUSIONS: Posteriorly repositioning the mandible produced a series of histological and morphological responses in the condyle, suggesting condylar and mandibular adaptation in rats.

scholarly journals Functional Changes of Temporomandibular Joint Mechanoreceptors Induced by Reduced Masseter Muscle Activity in Growing Rats

2009 ◽  
Vol 79 (5) ◽  
pp. 978-983 ◽  
Author(s):  
Takayoshi Ishida ◽  
Tadachika Yabushita ◽  
Kunimichi Soma
Keyword(s):  
Temporomandibular Joint ◽  
Muscle Activity ◽  
Masseter Muscle ◽  
Growth Period ◽  
Control Group ◽  
Functional Changes ◽  
Male Wistar Rats ◽  
Masseter Muscles ◽  
Experimental Group ◽  
Indirect Stimulation

Abstract Objective: To determine the influence of masseter muscle activity during growth on the functional characteristics of temporomandibular joint (TMJ) mechanoreceptors. Materials and Methods: Sixty-six 3-week-old male Wistar rats were divided into an experimental group, in which the masseter muscles were bilaterally resected at 3 weeks of age, and a control group. Single-unit activities of the TMJ mechanoreceptors were evoked by indirect stimulation of passive jaw movement. Electrophysiologic recordings of TMJ units were made at 5, 7, and 9 weeks of age. Results: During this period, the firing threshold of the TMJ units was significantly lower and the maximum instantaneous frequency of the TMJ units was significantly higher in the experimental group than in the control group. Conclusion: Reduced masseter activity during the growth period alters the response properties of TMJ mechanoreceptors.

scholarly journals Lactose malabsorption and colonic fermentations alter host metabolism in rats

2013 ◽  
Vol 110 (4) ◽  
pp. 625-631 ◽  
Author(s):  
Virginie Alexandre ◽  
Patrick C. Even ◽  
Christiane Larue-Achagiotis ◽  
Jean-Marc Blouin ◽  
François Blachier ◽  
...  
Keyword(s):  
Colonic Mucosa ◽  
Portal Blood ◽  
Control Group ◽  
Adult Rats ◽  
Lactose Malabsorption ◽  
Host Interactions ◽  
Enhanced Production ◽  
Host Metabolism ◽  
Experimental Group

Lactose malabsorption is associated with rapid production of high levels of osmotic compounds, such as organic acids and SCFA in the colon, suspected to contribute to the onset of lactose intolerance. Adult rats are lactase deficient and the present study was conducted to evaluatein vivothe metabolic consequences of acute lactose ingestion, including host–microbiota interactions. Rats received diets of 25 % sucrose (S25 control group) or 25 % lactose (L25 experimental group). SCFA and lactic acid were quantified in intestinal contents and portal blood. Expression of SCFA transporter genes was quantified in the colonic mucosa. Carbohydrate oxidation (Cox) and lipid oxidation (Lox) were computed by indirect calorimetry. Measurements were performed over a maximum of 13 h. Time, diet and time × diet variables had significant effects on SCFA concentration in the caecum (P< 0·001,P= 0·004 andP= 0·007, respectively) and the portal blood (P< 0·001,P= 0·04 andP< 0·001, respectively). Concomitantly, expression of sodium monocarboxylate significantly increased in the colonic mucosa of the L25 group (P= 0·003 att= 6 h andP< 0·05 att= 8 h). During 5 h after the meal, the L25 group's changes in metabolic parameters (Cox, Lox) were significantly lower than those of the S25 group (P= 0·02). However, after 5 h, L25 Cox became greater than S25 (P= 0·004). Thus, enhanced production and absorption of SCFA support the metabolic changes observed in calorimetry. These results underline the consequences of acute lactose malabsorption and measured compensations occurring in the host's metabolism, presumably through the microbiota fermentations and microbiota–host interactions.

scholarly journals Increase in the constrictor effects of Rho-kinase in skeletal muscle and coronary arteries of rats with chronic hypothyroidism

2018 ◽  
Vol 17 (4) ◽  
pp. 23-32
Author(s):  
D. K. Gaynullina ◽  
E. K. Selivanova ◽  
A. P. Sharova ◽  
O. S. Tarasova
Keyword(s):  
Skeletal Muscle ◽  
Gastrocnemius Muscle ◽  
Rho Kinase ◽  
Antithyroid Drug ◽  
Free Water ◽  
Control Group ◽  
Resistance Arteries ◽  
Adult Rats ◽  
Contractile Responses ◽  
Male Wistar Rats

Aim. The deficit of thyroid function is known to be accompanied by an increase in the overall peripheral vascular resistance. This work tested the hypothesis that long-term hypothyroidism leads to an increase in the vasoconstrictor effect of Rho-kinase in skeletal muscle and heart resistance arteries of adult rats.Materials and methods.Male Wistar rats consumed the antithyroid drug propylthiouracil (PTU) in drinking water (0.025%), starting at 10 weeks of age. The rats of the control group received PTU-free water. After 14 weeks, the contractile responses of the gastrocnemius muscle arteries (to the α1-adrenoceptor agonist methoxamine) and the septal coronary artery (to the thromboxane A2 receptor agonist U46619) were isometrically recorded. The contribution of the Rho-kinase to the arterial contractile responses was assessed using inhibitor Y27632 (3 μM).Results.The consumption of propylthiouracil was accompanied by a marked decrease of thyroid hormone concentrations and an increase in total cholesterol serum level as well as a decrease in body weight. Maximal contractile responses of studied arteries were also reduced in hypothyroid rats. However, basal tone and reactivity to the moderate concentrations of agonists in arteries of hypothyroid rats were increased compared to control animals. Y27632 significantly weakened the contractile responses of the arteries and negated the differences between the two groups of rats.Conclusion.Chronic hypothyroidism leads to an increase in the activity of the Rho-kinase signaling pathway in the arteries of the gastrocnemius muscle and heart, which results in the increase of the spontaneous tone of the arteries and their reactivity to agonists.

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