Interaction Between Oxytocin and Opioidergic System on Food Intake Regulation in Neonatal Layer Type Chicken

The aim of the current study was to determine possible interaction of central oxytocin and opioidergic system on food intake regulation in neonatal layer-type chicken. In experiment 1, FD₃ chicken ICV injected with control solution, oxytocin (10 µg), β-FNA (µ receptor antagonist, 5 µg) and oxytocin (10 µg)?+?β-FNA were injected. Experiments 2–6 were similar to experiments 1, except chicken injected with nor-BNI (κ receptor antagonist, 5 µg), NTI (δ receptor antagonist, 5 µg), DAMGO (µ receptor agonist, 62.25 pmol), U-50488H (κ receptor agonist, 10 nmol), DPDPE (δ receptor agonist, 20 pmol) instead of β-FNA. In experiment 7, control solution, DAMGO (125 pmol), d(CH2)5Tyr(Me)-[Orn8]-vasotocin (oxytocin antagonist, 5 µg) and DAMGO?+?d(CH2)5Tyr(Me)-[Orn8]-vasotocin were ICV injected to FD₃ chicken. Experiments 8 and 9 were similar to experiments 7, except chicken injected with U-50488H (30 nmol) and DPDPE (40 pmol) instead of DAMGO. Then, cumulative food intake was recorded at 30, 60 and 120 min after injection. According to the results, ICV injection of the oxytocin (10 µg) significantly decreased food intake compared to control group (P?<?0.05). Co-injection of the oxytocin?+?β-FNA and oxytocin?+?U-50488H significantly decreased hypophagic effect of the oxytocin (P?<?0.05). While, co-injection of the oxytocin?+?nor-BNI or oxytocin?+?DAMGO significantly amplified hypophagic effect of the oxytocin in chicken (P?<?0.05). In addition, ICV injection of DAMGO (125 pmol) significantly decreased cumulative food intake compared to control group (P?<?0.05). However, co-addministration of the DAMGO?+?(CH2)5Tyr(Me)-[Orn8]-vasotocin significantly decreased hypophagic effect of the DAMGO (P?<?0.05) in chicken. These results suggested there are interconnection between oxytocin and opioidergic system on central food intake regulation, which mediates via µ and κ opioidergic receptors in neonatal layer-type chicken.

     

Interaction Between Central Opioidergic and Glutamatergic Systems on Food Intake in Neonatal Chicks: Role of NMDA,AMPA and mGLU1 Receptors

The present study was designed to examine the role of opioidergic and glutamatergic systems on feeding behavior in neonatal meat-type chicken. In experiment 1, FD₃ neonatal broilers ICV injected with (A) saline, (B) DAMGO (µ-opioid receptor agonist, 125 pmol), (C) MK-801 (NMDA glutamate receptors antagonist, 15 nmol) and (D) combination of DAMGO plus MK-801. Experiments 2–5 were similar to experiment 1, except FD₃ chicks ICV injected with CNQX (AMPA glutamate receptors antagonist, 390 nmol), AIDA (mGLU₁ receptors antagonist, 2 nmol), LY341495 (mGLU₂ receptors antagonist, 150 nmol) and UBP1112 (mGLU₃ receptors antagonist, 2 nmol) instead of MK-801, respectively. In experiments 6–10, FD₃ chicks ICV injected as the same as procedure to the experiments 1–5, except to inject with DPDPE (δ-opioid receptor agonist, 40 nmol) instead of the DAMGO. The experiments 11–15 were similar to the experiments 1–5, except neonatal broilers ICV injected with U-50488H (κ-opioid receptor agonist, 30 nmol) instead of DAMGO. Then the cumulative food intake measured until 120 min post injection. According to the results, ICV injection of DAMGO, significantly decreased food intake (P?<?0.05) while DPDPE and U-50488H increased feeding behavior compared to the control group (P?<?0.05). Co-injection of the DAMGO?+?MK-801 and DAMGO?+?AIDA, significantly decreased DAMGO-induced hypophagia in neonatal chicks (P?<?0.05). Also, co-injection of the DPDPE?+?CNQX significantly amplified DPDPE induced feeding behavior (P?<?0.05). These results suggested interconnection between central opioidergic and glutamatergic systems on feeding behavior mediates via µ- and δ-opioid receptor with NMDA, AMPA and mGLU₁ receptors in FD₃ neonatal broilers. These findings may shed light on the circuitry underlying interconnection between central opioidergic and glutamatergic systems on feeding behavior.     

Interaction Between Nociceptin/Orphanin FQ and Adrenergic System on Food Intake in Neonatal Chicken

The information emerging from the studies demonstrates adrenergic system and nociceptin/orphanin FQ (N/OFQ) play a crucial role on appetite regulation but there is no information for their interaction. The purpose of this study was to examine the effects of intracerebroventricular (ICV) injection of prazosin (α₁ receptor antagonist), yohimbine (α₂ receptor antagonist), metoprolol (β₁ adrenergic receptor antagonist), ICI 118,551 (β₂ adrenergic receptor antagonist) and SR59230R (β₃ adrenergic receptor antagonist) on N/OFQ-induced hyperphagia by 3-h food-deprived neonatal broiler chicken. In experiment 1, chicken injected with saline, prazosin (10 nmol), N/OFQ (16 nmol) and co-injection of prazosin + N/OFQ. In experiment 2, ICV injection of saline, yohimbine (13 nmol), N/OFQ (16 nmol) and yohimbine + N/OFQ applied to the birds. In experiment 3, injections were saline, metoprolol (24 nmol), N/OFQ (16 nmol) and metoprolol + N/OFQ. In experiment 4, the birds received ICV injection of saline, ICI 118,551 (5 nmol), (C) N/OFQ (16 nmol) and co-administration of ICI 118,551 + N/OFQ. In experiment 5, chicken injected with saline, SR59230R (20 nmol), N/OFQ (16 nmol) and SR59230R + N/OFQ. Then, cumulative food intake was recorded until 120 min after injection. According to the results, ICV injection of N/OFQ significantly increased food intake (P < 0.001). The effect of N/OFQ significantly amplified by co-injection of N/OFQ + β₂ adrenergic receptor antagonist (P < 0.001). Also, administration of β₁ or β₃ adrenergic receptor antagonist had no effect on N/OFQ-induced hyperphagia (P > 0.05). These results suggest that the effect of N/OFQ on cumulative food intake is mediated via β₂ adrenergic receptors in neonatal chicken.     

Intracerebroventricular Injection of NMDA Receptor Antagonist Affects l-Arginine Induced Food Intake in Neonatal Layer Chicks

International Journal of Peptide Research and Therapeutics - Nowadays inquiry of possible interplay between different neurotransmitters in brain function is one of the major fields of interest for...     

The Relationship Between Daytime and Nighttime Food Intake in an Obese Night-Eater

Some obese individuals consume food during awakenings from nighttime sleep. Three studies were conducted on a 28-year-old morbidly obese male with chronic sleeping complaints and insignificant weight loss, despite self-reported daily caloric restriction: I. For 3 mo, the subject recorded food intake for 24-h periods. Mean daytime intake was 1286 kcal ± 386 (SD), and mean nighttime intake was 1036 kcal ± 487 (SD). Caloric values of daytime and nighttime intake were negatively correlated, r = ?0.22, df= 82, p<.05. II. Seven consecutive 24-h food intake recordings were obtained with an automated formula dispenser when the subject was an inpatient on a metabolic ward and received ad libitum formula as his sole food source. Mean daytime intake was 1245 ± 662 (SD), and mean nighttime intake was 231 ± 236 (SD). There was a non-significant negative correlation between daytime and nighttime intake, r = -0.32, df = 5, NS. III. The subject underwent polysomnographic studies on 2 non-consecutive nights, following the administration of either a low (600 kcal) or high (1800 kcal) daytime caloric condition. The subject, upon awakening from nighttime sleep, could eat from a platter of sandwich quarters placed at his bedside. The addition of 1200 kcal to daytime intake decreased nighttime intake by 654 kcal, or by 55% of the additional calories delivered during the day. The three studies (I, II, and III) show that daytime food intake can be negatively correlated with nighttime intake, and that daytime intake can influence nighttime intake in a documented obese night-eater.     

Interaction between the Dopaminergic and GABA-ergic Systems of the Cortex during Conditioning

Impulse activities were recorded from neurons of the sensorimotor cortex of cats, trained to perform a conditioned placing reaction, before, during, and after iontophoretic application of the synaptically active drugs dopamine (DA) and GABA. Our experiments demonstrated that in most cases isolated application of DA increased the frequency of the impulse activity and the number of spikes related to the placing reaction. On the other hand, GABA evoked decreases in both indexes characterizing the impulse activity. In the case of co-application of DA with GABA, we observed both increases and decreases in the background firing rate activity and in the number of spikes related to the placing reaction. Our results suggest that interaction between the DA-ergic and GABA-ergic systems is realized at the receptor level and cannot be interpreted in an oversimplified manner.     

The Crosstalk Between Brain Mediators Regulating Food Intake Behavior in Birds: A Review

International Journal of Peptide Research and Therapeutics - Appetite is controlled by a complex system of central and peripheral signals interacting to modulate the ingestion response. Several...     

The Effects of NPY and Insulin on Food Intake Regulation in Fish

Recent abundant studies report that in rodents starvation inducesincreased neuropeptide Y (NPY) mRNA expression and peptide secretionin the hypothalamus which reduces autonomic nervous activityand promotes food intake, and intracerebroventricular (ICV)injection of NPY has potent orexigenic effects. Conversely,the effect of insulin in the central nervous system is to inhibitfood intake and NPY biosynthesis and secretion. In mammals bodyfatness is regulated and insulin acts as one intake inhibitorysignal related to fatness. In salmon (Oncorhynchus sp.) we havedemonstrated a rise in NPY-like mRNA expression and a coincidentdecrease in plasma insulin levels during 2 to 3 weeks of starvation.Additionally, experimentally manipulating body fatness withhigh and low fat diets has demonstrated that body fatness affectsfood intake in teleost fishes, raising the possibility thatNPY and insulin act to regulate their food intake. Therefore,we hypothesized that as in rodents, ICV treatment with NPY wouldstimulate food intake while ICV insulin would reduce food intake.Preliminary results suggest that ICV NPY administration doesstimulate food intake in channel catfish (Ictalurus punctatus),but central injection of insulin has no effect. Results of treatmentswith the sulfated octapeptide of cholecystokinin and the recombinantfragment of rat leptin 22–56 are also discussed.     

Dopaminergic Receptors in Bovine Retina and Their Interaction with Thyrotropin-Releasing Hormone

A superfusion technique was employed to study the release of [3H]dopamine from isolated bovine retina. Only K+-stimulated release was observed from both light- and dark-adapted retina; release by other stimuli was from dark-adapted retina only. Light-evoked release of [3H]dopamine from dark-adapted retina was blocked by thyrotropin-releasing hormone (TRH), which has previously been identified as a retinal neuropeptide. TRH itself released small amounts of [3H]dopamine from dark-adapted retina. These results are interpreted as indicating that TRH acts as a modulator of dopaminergic activity in retina through the agency of presynaptic autoreceptors. Evidence of the existence of a feedback inhibition system, probably mediated by dopaminergic autoreceptors, was found by the inclusion of sulpiride, a dopaminergic D2 receptor antagonist in the perfusate, which, in a stereoselective manner, enhanced spontaneous and light-evoked release of [3H]dopamine. On the other hand, dopamine (1 microM) reduced these effects. TRH did not affect the high-affinity uptake system for dopamine in retina; this, then, could not account for the effects on release. Radioligand binding showed a specific, saturable high-affinity binding system for [3H]TRH, with an apparent KD of 2.2 nM and a Bmax of 23 fmol/mg protein in bovine retinal membranes. Displacement experiments showed that specific [3H]TRH binding was displaced in the nanomolar range by spiperone and in the micromolar range by dopamine, whereas L-(--)-sulpiride was virtually inactive in displacing [3H]TRH.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of Temperature on Energy Intake and Food Selection by Macaques

I examined the influence of temperature on food intake in 4 captive macaques in a room with controlled temperature. I gave them two types of artificial food pellets which were different in energy content per weight in 6 conditions of air temperature. Total energy intake of macaques increased as temperature decreased. Intake of low quality pellets increased significantly with decreasing temperature in 3 of 4 subjects. The other macaque, whose food intake was almost constant, decreased his body weight as ambient temperature decreased. These results suggest that energy requirements of macaques change with temperature as a result of changes in energy required for thermoregulation. Moreover, temperature influenced the selectivity of lower quality food. I discuss the pattern of food selection found in this experiment from the viewpoint of optimal foraging strategy.     

The Role of Explicit and Implicit Self-Esteem in Peer Modeling of Palatable Food Intake: A Study on Social Media Interaction among Youngsters

Objective

This experimental study investigated the impact of peers on palatable food intake of youngsters within a social media setting. To determine whether this effect was moderated by self-esteem, the present study examined the roles of global explicit self-esteem (ESE), body esteem (BE) and implicit self-esteem (ISE).

Methods

Participants (N = 118; 38.1% boys; M age 11.14±.79) were asked to play a computer game while they believed to interact online with a same-sex normal-weight remote confederate (i.e., instructed peer) who ate either nothing, a small or large amount of candy.

Results

Participants modeled the candy intake of peers via a social media interaction, but this was qualified by their self-esteem. Participants with higher ISE adjusted their candy intake to that of a peer more closely than those with lower ISE when the confederate ate nothing compared to when eating a modest (β = .26, p = .05) or considerable amount of candy (kcal) (β = .32, p = .001). In contrast, participants with lower BE modeled peer intake more than those with higher BE when eating nothing compared to a considerable amount of candy (kcal) (β = .21, p = .02); ESE did not moderate social modeling behavior. In addition, participants with higher discrepant or “damaged” self-esteem (i.e., high ISE and low ESE) modeled peer intake more when the peer ate nothing or a modest amount compared to a substantial amount of candy (kcal) (β = −.24, p = .004; β = −.26, p<.0001, respectively).

Conclusion

Youngsters conform to the amount of palatable food eaten by peers through social media interaction. Those with lower body esteem or damaged self-esteem may be more at risk to peer influences on food intake.     

Effect of Moxibustion on Dopaminergic and Serotonergic Systems of Rat Nucleus Accumbens

Acupuncture and moxibustion are traditional medical treatments that have come to play important roles in complementary and alternative medicines. Moxibustion also has a long history as a folk remedy in Japan, particularly due to the technical simplicity and selective efficacy on certain types of disease and distress. This study examined the effects of moxibustion focusing on the brain reward system, particularly in the nucleus accumbens. The effects of moxibustion stimulation at various sites and frequencies on monoamine levels of adult male Sprague-Dawley rats were examined using high-preformance liquid chromatography of dissected nucleus accumbens tissues. The rats weighing 290–310 g were divided into 3 groups according to the moxibustion point used: hindlimb, lumbar or parietal points. Each group was further divided into 3 subgroups, with stimulation for 10 consecutive days, for 1 day, or sham treatment (control). On each day of stimulation, 5 moxibustion cones with a peak temperature of 200°C were applied consecutively. Stimulation of any point on 1 day only did not change dopamine or serotonin levels, but lumbar stimulation significantly increased the metabolic turnover of dopamine. Conversely, stimulation for 10 consecutive days resulted in significantly decreased serotonin levels for hindlimb and parietal stimulations, and significantly increased 5-hydroxyindolacetic acid/serotonin ratio for hindlimb stimulation. These results suggest that the metabolic turnover of serotonin release may be accentuated by moxibustion in a reward-related brain area. Moxibustion over consecutive days, especially that to peripheral regions, appears most efficient to influence on monoamine levels in the nucleus accumbens. Special issue dedicated to Dr. Simo S. Oja     

单宁酸对棕色田鼠和小鼠食物选择、日食量和蛋白质消化率的影响

目的用不同浓度单宁酸（tannic acid,TA）处理后的花生喂养棕色田鼠（Lasiopodomys mandarinus）和小鼠（Mus musculus）,研究单宁酸对两种鼠食物选择倾向、食物摄入量、蛋白质消化率的影响。方法本研究的设计如下：1）选择一批棕色田鼠和小鼠,单笼饲养,自由饮水。用正常花生饲喂二周实验用棕色田鼠和小鼠,使其适应这种食物;2）随机选出棕色田鼠和小鼠各10只（雌雄各半）,单笼饲养。用经0%、5%、10%TA处理的花生饲喂供试鼠一周,观察和记录两种鼠对TA处理后花生的选择和取食特征;3）随机选出18只棕色田鼠和18只小鼠,单笼饲养,并各分为3组（每组均为6只）,按两种鼠分别命名为对照组、低单宁酸组、高单宁酸组,并分别用经0%、5%和10%TA处理的花生饲喂一周,测定两种鼠的食物摄入量;同时收集粪便,用凯氏定氮仪测定粗蛋白含量,计算蛋白质消化率。结果1）棕色田鼠和小鼠均优先选择无TA食物（P〈0.001）,二者间差异达显著性水平（P〈0.001）;2）食物中的TA降低棕色田鼠和小鼠的相对日食量（P〈0.001）和食物中蛋白质的消化率,随TA含量的升高,棕色田鼠和小鼠的相对日食量和蛋白质消化率均显著下降。结论TA降低棕色田鼠和小鼠的食物摄入量和食物中蛋白质的消化率。TA对鼠类的食物摄入量和蛋白质消化率的影响有种间差异性,小鼠对TA的适应性更强。     

Role of 5-HT3 Receptor on Food Intake in Fed and Fasted Mice

Background

Many studies have shown that 5-hydroxytryptamine (5-HT) receptor subtypes are involved in the regulation of feeding behavior. However, the relative contribution of 5-HT₃ receptor remains unclear. The present study was aimed to investigate the role of 5-HT₃ receptor in control of feeding behavior in fed and fasted mice.

Methodology/Principal Findings

Food intake and expression of c-Fos, tyrosine hydroxylase (TH), proopiomelanocortin (POMC) and 5-HT in the brain were examined after acute treatment with 5-HT₃ receptor agonist SR-57227 alone or in combination with 5-HT₃ receptor antagonist ondansetron. Food intake was significantly inhibited within 3 h after acute treatment with SR 57227 in fasted mice but not fed mice, and this inhibition was blocked by ondansetron. Immunohistochemical study revealed that fasting-induced c-Fos expression was further enhanced by SR 57227 in the brainstem and the hypothalamus, and this enhancement was also blocked by ondansetron. Furthermore, the fasting-induced downregulation of POMC expression in the hypothalamus and the TH expression in the brain stem was blocked by SR 57227 in the fasted mice, and this effect of SR 57227 was also antagonized by ondansetron.

Conclusion/Significance

Taken together, our findings suggest that the effect of SR 57227 on the control of feeding behavior in fasted mice may be, at least partially, related to the c-Fos expression in hypothalamus and brain stem, as well as POMC system in the hypothalamus and the TH system in the brain stem.     

The Mechanism of Food Intake in Tokophrya infusionum and Ultrastructural Changes in Food Vacuoles during Digestion*

SYNOPSIS Food intake in Tokophrya infusionum is preceded by penetration of the knob of the tentacle into the cytoplasm of the prey, Tetrahymena. Immediately thereafter, the membrane of the knob starts to invaginate into the lumen of the inner tube of the tentacle carrying with it the cytoplasm of the prey. At the proximal end of the tentacle, the invaginating membrane inflates, pinches off and forms a food vacuole. The mechanism is similar to that in amoebae during pinocytosis. The first few food vacuoles contain broken-up membranes, an indication that predigestion of prey cytoplasm takes place. This process is limited, however, to the part of cytoplasm around the knob since all food vacuoles formed later are composed of intact cytoplasmic organelles of Tetrahymena. Among them the most abundant and at the same time the most resistant to digestion are mitochondria and mucocysts. The ultrastructure of mitochondria is preserved very well during processing for electron microscopy and changes in their fine structure therefore serve conveniently as markers of the stage of digestion and of the age of food vacuoles. Digestion of mitochondria progresses over a period of several hours. They finally seem to degrade into glycogen-like particles. All components of the food vacuole reach this stage much earlier. Digestion proceeds further until the food vacuole is filled with a watery content of very low density. Digestion in such food vacuoles is completed. The complete digestion of the content of food vacuoles is of primary importance for Tokophrya, since this organism does not have a cytopyge thru which waste products could be eliminated.