Feeding Behavior In Rats Research Articles

The involvement of orexin-1 receptors in modulation of feeding and anxiety-like behavior in rats with complete Freund's adjuvant-induced temporomandibular joint disorder.

Orexin-A (OXA), a neuropeptide produced in the hypothalamus, is recognized for its role in modulating orofacial nociception and regulating feeding behaviors, as well as its impact on psychophysiological responses. This study investigated the role of orexin-1 receptors (OX1R) in modulating nociceptive behaviors induced by noxious stimulation of the temporomandibular joint (TMJ) and the associated changes in mood and feeding behaviors in rats with complete Freund's adjuvant (CFA)-induced temporomandibular disorders (TMDs). Bilateral cannulation of the lateral ventricles was performed in rats. To induce nociception, CFA was injected unilaterally into the left TMJ of the rats. Nociceptive behaviors were assessed using the hot plate and tail flick tests, while anxiety-like behavior and food intake were evaluated using an elevated plus maze (EPM) and a food preference device, respectively. The results demonstrated a significant increase in nociceptive scores and anxiety-like behaviors, along with reductions in water and food consumption following CFA injection. However, post-treatment with OXA at concentrations of 50 and 100pM/rat significantly decreased thermal nociceptive scores, alleviated anxiety-like behavior, and increased water and food intake. These beneficial effects were reversed when OXA was co-administered with SB-334867 (40nM/rat), an OX1R antagonist. Collectively, our findings suggest that OX1R signaling plays a role in the modulation of anxiety-like behavior and abnormalities in food intake in CFA-treated rats. Understanding the involvement of OXA and its receptors in CFA-induced TMJ nociception and behavioral changes may pave the way for potential therapeutic interventions targeting OX1R signaling in the management of TMD-associated symptoms.

Reducing binge eating behavior in rats using the novel ghrelin receptor antagonist Agrelax

BACKGROUND: Binge eating disorder is the most common eating disorder, characterized by recurrent episodes of binge eating during which a person consumes excessive amounts of food in the absence of hunger. These episodes of binge eating are usually accompanied by a feeling of lack of control with an inability to refrain from eating or stop eating once it has started. A rodent model of binge eating disorder shows that intermittent consumption of energy-dense foods induces binge eating behavior independent of weight gain. AIM: To study the effect of the ghrelin receptor antagonist Agrelax on compulsive overeating in rats. MATERIALS AND METHODS: The study involved 30 male Wistar rats. To model compulsive overeating, animals received high-calorie food (a mixture based on chocolate-nut butter spread) 3 times a week while maintaining free access to standard pelleted food and water. Compulsivity in behavior was assessed using the pellet burying test. The ghrelin receptor antagonist Agrelax was administered intranasally, 1 µg/1 µl, 10 µl in each nostril for 7 days. RESULTS: Compulsive behavior was assessed using the pellet burying test. The experimental group of animals receiving a high-calorie diet buried a significantly larger number of pellets than the control group (p 0.01). After a 7-day course of Agrelax, the number of buried balls decreased significantly, reaching the values of the control group (p 0.05). A technique for compulsive overeating in rats was developed by giving high-calorie food 3 times a week. After a 7-day course of Agrelax, the consumption of high-calorie foods significantly decreased (p 0.05). The daily consumption of standard feed in the group did not differ compared to the control group. However, after the course of Agrelax administration, the consumption of standard feed decreased. CONCLUSIONS: The data obtained suggest new ways of synthesizing peptide pharmacological agents based on ghrelin and its antagonists for the correction of food addiction.

Effect of mobile phone radiofrequency electromagnetic radiations on oxidative stress and feeding behaviour in Sprague Dawley (SD) rats

Objectives: Radiofrequency electromagnetic radiation (RF-EMR) from mobile phones is known to produce a stress response because of its effect on hypothalamus. Mobile phones have become an integral part of our lives with increasing usage not only in terms of number of users but also increase in talk time. The present study aimed to study the effect of mobile phone radiofrequency electromagnetic radiations on oxidative stress and feeding behaviour assessment in Sprague Dawley (SD) rats. Materials and Methods: Twelve male SD rats of 10–12 weeks old, weighing 180–220 g, were housed and allowed to acclimatise in a room with 12:12 h light-dark cycle with ad libitum amount of food and reverse osmosis (RO) water before the start of the study. Then, rats were divided into control and RF-EMR exposed groups, and everyday feed intake and body weight were measured. At the end of the study period, blood sample was collected through retro orbital puncture for biochemical investigations. Results: The present study showed significant increase in malondialdehyde and serum corticosterone levels and decrease feeding behaviour in rats exposed to RF-EMR in rats exposed to RF-EMR. Conclusion: This study proves that mobile RF-EMR causes oxidative stress and oxidative damage leading to decreased feeding behaviour in SD rats.

Preclinical comparison of antinociceptive effects between ibuprofen, diclofenac, naproxen, and acetaminophen on acid-stimulated body stretching and acid-depressed feeding behaviors in rats.

Pain is a major problem that burdens the health and economy of societies worldwide. Nonsteroidal anti-inflammatory drugs (NSAIDs) are over-the-counter medications that are widely indicated for mild to moderate pain conditions. Clinically, the selection of a medication among this class is mainly based according to both patient's and doctor's previous experiences. Herein, we studied differences in therapeutic efficacies among the most commonly prescribed NSAIDs and acetaminophen in inflammatory pain rat model. Body stretching and food consumption behaviors were assessed after intraperitoneal administration of lactic acid. Initially, different concentrations of lactic acid were evaluated in adult male rats in both behavioral models. Acid concentrations of 1.8 and 3.2% were selected to assess the effects of ibuprofen, diclofenac, naproxen, and acetaminophen in body stretching and feeding behaviors, respectively. In the feeding study, food restriction for 1-24 h prior to feeding studies was assessed at first, and 24 h was selected for further tests. Acetaminophen (100 mg/kg), diclofenac (10 mg/kg), ibuprofen (10-32 mg/kg), and naproxen (3.2-10 mg/kg) significantly decreased acid-stimulated body stretching. Likewise, acetaminophen (100 mg/kg), diclofenac (10 mg/kg), and ibuprofen (32 mg/kg) increased food consumption significantly after 3.2% lactic acid. There were no significant differences between different test drugs efficacies in both stretching and feeding behaviors. In conclusion, feeding behavior provides a good appraisal for pain and analgesic drugs in preclinical studies. There were comparable efficacies between all tested medications in both lactic acid-stimulated body stretching and -depressed feeding behaviors.

Long-term changes in oral feeding behaviors of growing rats.

Oral feeding is critical for survival in both humans and animals. However, few studies have reported quantitative behavioral measures associated with the development of oral feeding behaviors. Therefore, the present study investigated developmental changes in the oral feeding behaviors of rats by quantitatively assessing pasta eating and licking behaviors. In the pasta eating test, the time to finish pasta sticks of three different thicknesses (Φ = 0.9, 1.4, and 1.9mm, 4cm long) was recorded between postnatal day 29 (P29) and P49, because all rats were able to finish eating these pasta sticks on P29. A developmental decrease in the time to finish pasta sticks of all thicknesses was observed during the initial period of recordings and plateaued before P35. The extent of this decrease was dependent on the thickness of pasta sticks. In the licking test, the number of licks per 10s and the total intake volume during the test were recorded between P19 and P49, because all rats were able to access and lick the solution on P19. The time courses of developmental increases in the number of licks and the total intake volume were similar to the results obtained in the pasta eating test. Collectively, these results suggest that developmental changes in pasta eating and licking behaviors markedly differed between the weanling and periadolescent periods. The present study also demonstrated the applicability of the pasta eating and licking tests to the quantification of developmental changes in the oral feeding behaviors of rats.

Deficient Central Leptin Signaling “In Vivo” Alters Hypothalamic Levels of Circadian Clock Proteins Changing the Diurnal Eating Behavior in Rats

BackgroundLeptin, acting at CNS, decreases food intake (FI), body weight (BW) and adiposity, while circadian dysfunction induces hypothalamic leptin resistance associated to increased adiposity. Hence, we hypothesized that partial inhibition of hypothalamic leptin signaling “in vivo” would alter circadian rhythms resulting in changes in diurnal eating behaviors leading to increased adiposity and peripheral insulin resistance.Methods3‐months‐old Wistar rats were randomly assigned in two different groups: rats infused “in vivo” with saline (PBS) (n=12) or rats infused with a leptin antagonist (SLA) (0.2 micrograms/day) (n=12) via icv minipump insertion for 21 days. On day 0, rats were individually housed in metabolic cages and maintained for 21 days measuring daily BW, FI and locomotor activity. Hypothalamic proteomic analysis (n=6 per group) was carried out to determine if hypothalamic circadian proteins could be altered upon chronic SLA infusion. On day 21 and before sacrifice, one group of rats infused with PBS or SLA (n=6 per group) were injected icv with 100 ng of rat leptin in a volume of 2 microliters. 30 min later rats were euthanatized.ResultsSLA infusion decreased leptin‐induced phosphorylation of pY705‐STAT3 at the hypothalamus sustaining the induction of central leptin resistance upon chronic SLA administration. As a result, daily FI, final BW and visceral adiposity increased in SLA‐infused rats. Remarkedly, the diurnal eating behavior was altered in the SLA group of rats. In fact, daily FI was significantly increased by 48% only during the light phase in SLA infused vs PBS treated control rats, while in the dark phase FI increased less than 10% in the SLA group compared with control PBS‐infused rats. Moreover, SLA‐infused rats develop peripheral insulin resistance assessed by HOMA‐IR at the end of the treatment. Hypothalamic proteomic analysis revealed significant changes in 446 proteins, 266 were up‐regulated and 180 down‐regulated upon SLA infusion. Interestingly, proteins involved in the transcriptional activity of BMAL1/CLOCK were altered in SLA‐infused rats. Paraspeckle component 1, involved in the negative regulation of BMAL1/CLOCK, was over‐represented, while vasopressin‐neurophysin 2 copeptin, a positive regulator of circadian gene expression, was under‐represented.ConclusionOur results suggest that deficient hypothalamic leptin signaling is associated to circadian dysfunction which leads to changes in the diurnal eating behavior in rats resulting in increased adiposity and peripheral insulin resistance.

Effect of anaerobic resistance training on gastric emptying of solids, nutritional parameters and food behavior in the rats treated with dexamethasone

Dexamethasone (Dexa) is a potent glucocorticoid that can trigger side effects, such as neuromuscular, cardiovascular, and gastric motility disorders. Exercise can ameliorate gastrointestinal disorders. However, it is not clear whether exercise can modulate the side effects of using Dexa on gastric motility. To investigate the role of anaerobic resistance training (ART) on gastric motility and feeding behavior of rats treated with dexamethasone, rats were divided into three groups: control (Ctrl), dexamethasone (Dexa), and anaerobic resistance training + dexamethasone (ARTDexa). Anaerobic resistance training (ART) consisted of climbing a vertical ladder 5 days/week (with intensity of 50% to 100% of the maximum overload/8 weeks). At the end of the ART or control period, the rats received Dexa (1 mg/kg i.p) for 10 consecutive days. In the end, we evaluated anthropometric parameters and feeding behavior, heart rate, gastric emptying, and lipid profile in all groups. We observed significant decrease (p < 0.05) in body weight and food intake in the Dexa and ARTDexa groups compared to the control. Dexa promoted significant tachycardia (p < 0.05) and a decrease (p < 0.05) in the r-r’ interval. The ART significantly prevented (p < 0.05) cardiovascular effects. Dexa induced a decrease (p < 0.05) in gastric emptying compared to the control group. On the other hand, ART significantly prevented (p < 0.05) the decrease in gastric emptying compared to Dexa. The chronic use of Dexa caused tachycardia, decreased food intake, and decreased gastric emptying. The ART modulated cardiovascular parameters, improving tachycardia. In addition, this exercise prevented gastric dysmotility induced by dexamethasone.

Correlations between sol viscosity of the partially degraded konjac glucomannan and appetite response of rats

Understanding the correlations between dietary fibers' physical properties and postprandial appetite response helps to design novel functional products with satiety enhancing capability. In the present study, the partially degraded konjac glucomannan (Pd-KGM) was obtained by applying the heterogeneous hygrothermal degradation method, and its flow behavior was studied for guiding the preparation of sols with equi-concentration but differed in viscosity. The appetite-regulating effects derived from the sol viscosity were explored by monitoring the appetite hormone response and the feeding behavior of rats after they were given the Pd-KGM sols. By lowering the secretion of ghrelin, elevating the plasma concentration of GLP-1, PYY3–36, and CCK-8, and stabilizing blood glucose and insulin fluctuation, the sol with increased viscosity showed an improved satiety-enhancing capability. Moreover, the transition point from feeding to resting was advanced in rats given a more viscous sol, resulting in a significantly decreased feed intake (p < 0.05). We further explored the correlations between sol viscosity and its nutritional effects relating to appetite regulation depending on the quantitative data obtained in this study. Excluding the plasma glucose and CCK-8, a strong linear correlation (Pearson coefficient > 0.7) emerged between the appetite hormone and the sol viscosity, especially for the GLP-1, which its Pearson coefficient was 0.946, indicating a very highly correlated relationship between them. Thus, these results revealed the feasibility of regulating appetite by taking advantage of sol viscosity.

Tympanic Membrane Rupture During Stereotaxic Surgery Disturbs the Normal Feeding Behavior in Rats.

Stereotactic surgery is a widely used procedure in neuroscience research to study the brain’s regulation of feeding behavior. In line with this notion, this study aims to assess how food consumption and feeding patterns are affected in response to the use of auditory bars that preserve or damage the tympanic membrane during stereotactic surgery. Our previous observations led us to hypothesize that the traumatic tympanic membrane rupture affects food intake and feeding patterns in rats undergoing stereotactic procedures. Thereby, female and male rats were cannulated in the third ventricle (3V) using both types of auditory bars. Post-surgical pain was assessed using the grimace scale. Food intake, meal patterns and weight gain or loss were analyzed for 5–7 consecutive days after surgery. Normal food intake, increased body weight and regular meal patterns were observed from postoperative day 2 when the stereotactic procedure was performed using auditory bars that maintain the integrity of the tympanic membrane. However, tympanic membrane rupture prevented the expected recovery of food intake and body weight. This effect was accompanied by an alteration in eating patterns, which was persistent over 7 days of recovery. Thus, tympanic membrane preservation during surgery is necessary to evaluate short-term feeding patterns. This study demonstrates auditory bars that do not damage the tympanic membrane should be used when performing stereotactic surgery for subsequent analysis of rat behavior.

Effects of acupuncture on Nod-like receptor protein 3 inflammasome signal pathway in the prefrontal cortex of rat with depression

To observe the influence of acupuncture on the expression of pivotal molecules of Nod-like receptor protein 3(NLRP3) inflammasome signal pathway in the prefrontal cortex of rats with depression, so as to explore the underlying mechanism of acupuncture on treatment of depression. SD rats were randomly divided into 4 groups (8 rats/group)，namely control, model, acupuncture and fluoxetine groups. The depression model was established by using chronic unpredictable mild stress for 6 weeks. During modeling, acupuncture (10 min)was applied to "Baihui"(GV20) and "Yintang"(EX-HN3) for rats of the acupuncture group once a day, with 1 day interval after consecutive 6 day-period for 36 days. Fluoxetine was given (10 mg/kg，1 mg/mL) by gavage to rats of the fluoxetine group every day during modeling for 42 days. The novelty-suppressed feeding test was used to observe feeding behavior of rats. The expressions of NLRP3 and apoptosis associated speck like protein containing a CARD (ASC), Caspase-1, and contents of IL-1β in the prefrontal cortex were detected by Western blot, immunohistoche-mistry and ELISA, separately. Compared with the control group, the latency of the novelty-suppressed feeding, and the expressions of NLRP3, ASC, Caspase-1 and IL-1β content in the prefrontal cortex of the model group were significantly increased (P<0.01). Following the interventions, the latency of the noveltysuppressed feeding，and the expressions of NLRP3, ASC, Caspase-1 and IL-1β content in the prefrontal cortex in the acupuncture and fluoxetine groups were significantly decreased (P<0.05，P<0.01). There was no significant differences in the above indicators between the acupuncture group and the fluoxetine group (P>0.05). Acupuncture could inhibit the expression of NLRP3 inflammasome signal pathway in the pre-frontal cortex, and reduce the inflammation in the brain, which may mediate the anti-depressant effect of acupuncture.

Effects of soy protein isolate hydrolysates on cholecystokinin released by rat intestinal mucosal cells and food intake in rats.

Soy protein isolate hydrolysates (SPIH) were prepared from soy protein isolate (SPI). Effects of SPIH on a satiety signal cholecystokinin (CCK) and feeding behavior in rats were investigated. SPIH induced more CCK release (164.66 ± 2.40pg/mL) by rat intestinal mucosal cells than SPI (143.33 ± 3.71pg/mL). Meal size (MS), intermeal interval (IMI), and satiety ratio (SR = MS/IMI) of rats received different daily doses of SPIH or dietary fiber were detected for 40days. A 100mg/kg dose of SPIH resulted in a greater SR than an identical dose of dietary fiber, while a 300mg/kg dose resulted in a less MS and IMI. A 500mg/kg dose of SPIH had similar effects to the same dose of dietary fiber on reducing MS, extending IMI, and increasing SR, but resulted in a significantly less body weight at the end of the experiment (318.15 ± 17.83g) than the dietary fiber group (340.28 ± 6.15g).

Influence of the physical exercise on decrease in the gastric emptying and alter appetite and food behavior in rats dexamethasone-treatment

The chronic use of Dexamethasone (Dex) induced hyperglycemia and insulin resistance. On the other hand, physical exercise attenuates the symptoms induced by Dex in many physiological systems. However, the effect of the exercise on the changes in gastric motility induced by dexamethasone remains unknown. We hypothesized that low-intensity aerobic exercise modulates the metabolic effects induced by Dex-treatment by modifying the gastrointestinal function and feeding behavior in rats. Male rats were distributed into the following groups: Control (Ctrl), Dex (1.0 mg/kg, i.p.), Exercise (Ctrl + Exercise 5%) and (Dex1.0 + Exercise 5%). The exercise protocol was swimming for 5 consecutive days. We assessed the murinometric and nutritional indices, food intake, blood glucose by (ipGTT) and the gastric emptying rate of a liquid test meal were assessed in all rats. We observed a significant decrease (p < .05) in the gastric emptying in Dex1.0 group in relation to Ctrl group. The exercise prevented decrease in the gastric emptying (p < .05) in Dex1.0 + EX5% group when compared with Dex1.0 groups. The Dex1.0 group induced a significantly increase (p < .05) in glycaemia vs Ctrl group. The hyperglycemia was improving (p < .05) in the Dex1.0 + Ex5% compared with Dex1.0 groups. We observed a positive correlation (p < .05, and r = 0.7065) between gastric retention vs glycaemia in the Dex1.0 groups. The Dex1.0 reduced (p < .05) the body weight and altered body composition, promoting hypophagia. IL-6 increased (p < .05) at gastric fundus in Ex5% compared with Ctrl groups. In conclusion, the use of Dex1.0 decreases gastric emptying, promotes hyperglycemia and modifies feeding behavior. The low-intensity exercise prevents hyperglycemia, thus improving gastric dysmotility without improving the anthropometric parameters.

Finding the balance between model complexity and performance: Using ventral striatal oscillations to classify feeding behavior in rats.

The ventral striatum (VS) is a central node within a distributed network that controls appetitive behavior, and neuromodulation of the VS has demonstrated therapeutic potential for appetitive disorders. Local field potential (LFP) oscillations recorded from deep brain stimulation (DBS) electrodes within the VS are a pragmatic source of neural systems-level information about appetitive behavior that could be used in responsive neuromodulation systems. Here, we recorded LFPs from the bilateral nucleus accumbens core and shell (subregions of the VS) during limited access to palatable food across varying conditions of hunger and food palatability in male rats. We used standard statistical methods (logistic regression) as well as the machine learning algorithm lasso to predict aspects of feeding behavior using VS LFPs. We were able to predict the amount of food eaten, the increase in consumption following food deprivation, and the type of food eaten. Further, we were able to predict whether the initiation of feeding was imminent up to 42.5 seconds before feeding began and classify current behavior as either feeding or not-feeding. In classifying feeding behavior, we found an optimal balance between model complexity and performance with models using 3 LFP features primarily from the alpha and high gamma frequencies. As shown here, unbiased methods can identify systems-level neural activity linked to domains of mental illness with potential application to the development and personalization of novel treatments.

An Ultradian Feeding Schedule in Rats Affects Metabolic Gene Expression in Liver, Brown Adipose Tissue and Skeletal Muscle with Only Mild Effects on Circadian Clocks.

Restricted feeding is well known to affect expression profiles of both clock and metabolic genes. However, it is unknown whether these changes in metabolic gene expression result from changes in the molecular clock or in feeding behavior. Here we eliminated the daily rhythm in feeding behavior by providing 6 meals evenly distributed over the light/dark-cycle. Animals on this 6-meals-a-day feeding schedule retained the normal day/night difference in physiological parameters including body temperature and locomotor activity. The daily rhythm in respiratory exchange ratio (RER), however, was significantly phase-shifted through increased utilization of carbohydrates during the light phase and increased lipid oxidation during the dark phase. This 6-meals-a-day feeding schedule did not have a major impact on the clock gene expression rhythms in the master clock, but did have mild effects on peripheral clocks. In contrast, genes involved in glucose and lipid metabolism showed differential expression. In conclusion, eliminating the daily rhythm in feeding behavior in rats does not affect the master clock and only mildly affects peripheral clocks, but disturbs metabolic rhythms in liver, skeletal muscle and brown adipose tissue in a tissue-dependent manner. Thereby, a clear daily rhythm in feeding behavior strongly regulates timing of peripheral metabolism, separately from circadian clocks.

Incubation of feeding behavior is regulated by neuromedin U receptor 2 in the paraventricular nucleus of the hypothalamus

A diet of energy-dense food, characterized mainly as a high-fat diet, leads to a persistent excessive consumption defined as overeating. According to the National Institute of Health, more than 2 in 3 adults in the United States are overweight or obese, straining our healthcare system with epidemic proportions. Diets that include abstaining from high-fat foods, ironically, result in an increase in motivation and craving for said high-fat foods, defined as an incubation effect because the behavior aids in developing overeating. Previously, we have shown that modulation of neuromedin U receptor 2 (NMUR2) in the paraventricular nucleus of the hypothalamus (PVN) results in increased food intake and motivation for energy-dense foods. Here, we continue our focus on NMUR2 in the PVN, but in relation to the incubation effect on craving for high-fat food. We employed a model for incubation of craving by having rats abstain from high-fat foods for 30 days before undergoing intake of fatty food on fixed ratio and progressive ratio schedules of reinforcement, and then assess their response to reactivity to cues. Using this model, we compared the feeding behaviors of rats that underwent an mRNA knockdown of the NMUR2 in the PVN to controls after both underwent a 30-day abstinence from high-fat foods. Our results show knockdown of NMUR2 in the PVN blocks the incubation of feeding behavior for food-related cues and high-fat foods.

ラット視床下部におけるペプチド性摂食調節 : ニューロペプチドYとガラニンの役割と摂食障害への関与について(摂食障害の病態と治療)(第36回日本心身医学会総会)

ラット視床下部におけるペプチド性摂食調節 : ニューロペプチドYとガラニンの役割と摂食障害への関与について(摂食障害の病態と治療)(第36回日本心身医学会総会)

Pharmacological activation of RXFP3 is not orexigenic in C57BL/6J mice.

The neuropeptide relaxin-3 and its cognate G-protein-coupled receptor, RXFP3, have been implicated in the control of feeding behaviour in rats. For example, relaxin-3-positive projections and RXFP3 are present within hypothalamic feeding circuits, and icv injection of human relaxin-3 (-0.2 to 1.0 nmol) robustly increases feeding behaviour in satiated rats. To explore whether this action is conserved in other experimental species, the present study examined feeding behaviour in C57BL/6J mice following RXFP3 modulation, as mice display near identical regional distribution patterns of relaxin-3/RXFP3, and relaxin-3/RXFP3 signalling has been shown to modulate behavioural arousal in both species. Central injection of the RXFP3 agonists R3/I5 or H3 relaxin (0.5 nmol, icv) did not alter chow consumption in satiated mice relative to vehicle controls, during the 60 min after treatment. Furthermore, relaxin-3 knockout mice displayed similar basal 24-h chow consumption and 1-h palatable food consumption to wildtype littermate controls; although further studies involving acute pharmacological antagonism of RXFP3 in WT mice are required to eliminate the likelihood of compensation in these life-long relaxin-3 deficient mice. Taken together, these findings are in contrast to the potent orexigenic effects of RXFP3 activation observed in rats, and may reflect differential RXFP3 expression within hypothalamic neuron populations in the rat and mouse, or differences in signalling upstream or downstream of relaxin-3/RXFP3 networks in these two species.

The effects of intracerebroventricular infusion of irisin on feeding behaviour in rats

Irisin, a novel exercise-induced myokine, has attracted attention with its effects on energy metabolism. This study was conducted to determine the possible effects of irisin on nutritional behaviour.In this study, 40 male Wistar Albino rats were separated into 4 groups (n=10 for each group). Osmotic mini-pumps were connected to metal cannulas implanted to lateral ventricle; and artificial cerebrospinal fluid (vehicle), and 10 and 100nM of irisin was infused for 7days. The daily food and water consumptions and body weights of rats were followed up. After the infusion, the animals were killed, and the hypothalamus and blood samples were collected. NPY, POMC, and UCP2 mRNA levels in the hypothalamus were examined by RT-PCR. In serum, leptin and ghrelin levels as well as the levels of metabolic parameters were measured by using ELISA.It was determined that irisin administration increased the daily food consumption (p<0.05), without causing significant changes in water consumption and body weight. Irisin also caused increases in ghrelin level in circulation and NPY and UCP2 mRNA levels in the hypothalamus, whereas it decreased the leptin level in circulation and POMC mRNA levels in the hypothalamus (p<0.05). Otherwise, irisin caused decrease in LDL, triglycerides and cholesterol levels, while increasing HDL and glucose levels (p<0.05).Results indicates that long-term irisin treatment increases food intake without increasing body weight associated with increased ghrelin, NPY and UCP2 mRNAs, and decreased leptin and POMC mRNA in the hypothalamus.

κ-,δ-,μ-オピオイドペプチドレセプター作動薬脳室内投与によるラット摂食行動亢進効果

κ-,δ-,μ-オピオイドペプチドレセプター作動薬脳室内投与によるラット摂食行動亢進効果

ラット摂食行動における中枢内因性オピオイドペプチドの役割 : α_2-アドレナリン系ならびにGABA系との関連性

ラット摂食行動における中枢内因性オピオイドペプチドの役割 : α_2-アドレナリン系ならびにGABA系との関連性