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Objective: To investigate the effects of moderate‐intensity aerobic exercise on appetite control parameters, appetite perceptions, and energy intake in sedentary males with obesity. Design: Eleven males with obesity (body fat percentage 36.5 ± 2.5%, body mass index 35.3 ± 4.2 kg/m2, V̇O2peak 29 ± 3.1 mL·kg−1·min−1) completed two experimental sessions: (1) no exercise (CTRL) and (2) 60 min of moderate‐intensity cycling exercise at 60% V̇O2peak (MICT) in a crossover design. Blood analysis included growth differentiation factor 15 (GDF‐15), total ghrelin, peptide tyrosine tyrosine3–36 (PYY3–36), total glucagon‐like peptide‐1 (GLP‐1), insulin, and glucose, as well as subjective appetite perceptions were measured in specific intervals. A standard breakfast at 0 h and an ad libitum meal postexercise was provided. Result: GDF‐15 (95% confidence interval [CI]: [2.48–27.28] ng/L, p = 0.021) increased immediately following MICT compared to CTRL. However, there were no differences for PYY3–36 (p = 0.480, ηp2=0.025 ${\eta }_{p}^{2}=0.025$), total ghrelin (p = 0.646, ηp2=0.011 ${\eta }_{p}^{2}=0.011$), and total GLP‐1 (p = 0.451, ηp2=0.029 ${\eta }_{p}^{2}=0.029$) between sessions. Appetite perceptions (95% CI: [(−20.38)–(−6.16)] mm, p = 0.001) were suppressed following MICT though energy intake was not different between the sessions (95% CI: [(−1904.9)–928.1] kJ, p = 0.480). Conclusion: Sixty minutes of MICT increased GDF‐15 while suppressing appetite perceptions in individuals with obesity. There was no energy compensation postexercise. [ABSTRACT FROM AUTHOR]

The first systematic reviews of the effects of exercise on appetite‐regulation and energy intake demonstrated changes in appetite‐regulating hormones consistent with appetite suppression and decreases in subsequent relative energy intake over a decade ago. More recently, an intensity‐dependent effect and several potential mechanisms were proposed, and this review aims to highlight advances in this field. While exercise‐induced appetite suppression clearly involves acylated ghrelin, glucagon‐like peptide‐1 may also be involved, though recent evidence suggests peptide tyrosine tyrosine may not be relevant. Changes in subjective appetite perceptions and energy intake continue to be equivocal, though these results are likely due to small sample sizes and methodological inconsistencies. Of the proposed mechanisms responsible for exercise‐induced appetite suppression, lactate has garnered the most support through in vitro and in vivo rodent studies as well as a growing amount of work in humans. Other potential modulators of exercise‐induced appetite suppression may include sex hormones, growth‐differentiation factor 15, Lac‐Phe, brain‐derived neurotrophic factor, and asprosin. Research should focus on the mechanisms responsible for the changes and consider these other modulators (i.e., myokines/exerkines) of appetite to improve our understanding of the role of exercise on appetite regulation. [ABSTRACT FROM AUTHOR]

Commercial culture of channel catfish (Ictalurus punctatus) occurs in earthen ponds that are characterized by diel swings in dissolved oxygen concentration that can fall to severe levels of hypoxia, which can suppress appetite and lead to suboptimal growth. Given the significance of the hypothalamus in regulating these processes in other fishes, an investigation into the hypothalamus transcriptome was conducted to identify specific genes and expression patterns responding to hypoxia. Channel catfish in normoxic water were compared with catfish subjected to 12 h of hypoxia (20% oxygen saturation; 1.8 mg O2/L; 27°C) followed by 12 h of recovery in normoxia to mimic 24 h in a catfish aquaculture pond. Fish were sampled at 0-, 6-, 12-, 18-, and 24-h timepoints, with the 6- and 12-h samplings occurring during hypoxia. A total of 190 genes were differentially expressed during the experiment, with most occurring during hypoxia and returning to baseline values within 6 h of normoxia. Differentially expressed genes were sorted by function into Gene Ontology biological processes and revealed that most were categorized as "response to hypoxia," "sprouting angiogenesis," and "cellular response to xenobiotic stimulus." The patterns of gene expression reported here suggest that transcriptome responses to hypoxia are broad and quickly reversibly with the onset of normoxia. Although no genes commonly reported to modulate appetite were found to be differentially expressed in this experiment, several candidates were identified for future studies investigating the interplay between hypoxia and appetite in channel catfish, including adm, igfbp1a, igfbp7, and stc2b. NEW & NOTEWORTHY: Channel catfish are an economically important species that experience diel episodic periods of hypoxia that can reduce appetite. This is the first study to investigate their transcriptome from the hypothalamus in a simulated 24-h span in a commercial catfish pond, with 12 h of hypoxia and 12 h of normoxia. The research revealed functional groups of genes relating to hypoxia, angiogenesis, and glycolysis as well as individual target genes possibly involved in appetite regulation. Listen to this article's corresponding podcast at https://apspublicationspodcast.podbean.com/e/channel-catfish-transcriptomic-response-to-hypoxia/. [ABSTRACT FROM AUTHOR]

Abstract Objective To investigate the effects of moderate‐intensity aerobic exercise on appetite control parameters, appetite perceptions, and energy intake in sedentary males with obesity. Design Eleven males with obesity (body fat percentage 36.5 ± 2.5%, body mass index 35.3 ± 4.2 kg/m2, V̇O2peak 29 ± 3.1 mL·kg−1·min−1) completed two experimental sessions: (1) no exercise (CTRL) and (2) 60 min of moderate‐intensity cycling exercise at 60% V̇O2peak (MICT) in a crossover design. Blood analysis included growth differentiation factor 15 (GDF‐15), total ghrelin, peptide tyrosine tyrosine3–36 (PYY3–36), total glucagon‐like peptide‐1 (GLP‐1), insulin, and glucose, as well as subjective appetite perceptions were measured in specific intervals. A standard breakfast at 0 h and an ad libitum meal postexercise was provided. Result GDF‐15 (95% confidence interval [CI]: [2.48–27.28] ng/L, p = 0.021) increased immediately following MICT compared to CTRL. However, there were no differences for PYY3–36 (p = 0.480, ηp2=0.025), total ghrelin (p = 0.646, ηp2=0.011), and total GLP‐1 (p = 0.451, ηp2=0.029) between sessions. Appetite perceptions (95% CI: [(−20.38)–(−6.16)] mm, p = 0.001) were suppressed following MICT though energy intake was not different between the sessions (95% CI: [(−1904.9)–928.1] kJ, p = 0.480). Conclusion Sixty minutes of MICT increased GDF‐15 while suppressing appetite perceptions in individuals with obesity. There was no energy compensation postexercise.

Abstract Background Cyproheptadine is an easily available over-the-counter first-generation antihistaminic that is often used as an appetite stimulant. Although it is usually a safe drug, rare instances of drug-induced liver injury may occur. Case presentation We report a case of cholestatic liver injury secondary to cyproheptadine in a young pharmacy student with chronic hepatitis B and review the literature of cyproheptadine-induced liver injury. Conclusion Although cyproheptadine is largely a safe drug, its potential for significant liver toxicity cannot be ignored.

Alzheimer's disease (AD) remains a significant health challenge, with an increasing prevalence globally. Recent research has aimed to deepen the understanding of the disease pathophysiology and to find potential therapeutic interventions. In this regard, G protein-coupled receptors (GPCRs) have emerged as novel potential therapeutic targets to palliate the progression of neurodegenerative diseases such as AD. Orexin and cannabinoid receptors are GPCRs capable of forming heteromeric complexes with a relevant role in the development of this disease. On the one hand, the hyperactivation of the orexins system has been associated with sleep–wake cycle disruption and Aβ peptide accumulation. On the other hand, cannabinoid receptor overexpression takes place in a neuroinflammatory environment, favoring neuroprotective effects. Considering the high number of interactions between cannabinoid and orexin systems that have been described, regulation of this interplay emerges as a new focus of research. In fact, in microglial primary cultures of APPSw/Ind mice model of AD there is an important increase in CB2R–OX1R complex expression, while OX1R antagonism potentiates the neuroprotective effects of CB2R. Specifically, pretreatment with the OX1R antagonist has been shown to strongly potentiate CB2R signaling in the cAMP pathway. Furthermore, the blockade of OX1R can also abolish the detrimental effects of OX1R overactivation in AD. In this sense, CB2R–OX1R becomes a new potential therapeutic target to combat AD. [ABSTRACT FROM AUTHOR]

Background: Cyproheptadine is an easily available over-the-counter first-generation antihistaminic that is often used as an appetite stimulant. Although it is usually a safe drug, rare instances of drug-induced liver injury may occur. Case presentation: We report a case of cholestatic liver injury secondary to cyproheptadine in a young pharmacy student with chronic hepatitis B and review the literature of cyproheptadine-induced liver injury. Conclusion: Although cyproheptadine is largely a safe drug, its potential for significant liver toxicity cannot be ignored. [ABSTRACT FROM AUTHOR]

In living organisms, the central control of nutrition is a highly complex and vital mechanism. Central control of nutrition occurs in various regions of the brain, with the hypothalamus being the most important of which is the hypothalamus. The hypothalamus controls feeding behaviors through neural circuits, specialized nuclei, and central neurotransmitters. Different hypothalamic nuclei involved in regulating food intake include ARC, PVN, LHA, VMH, and DMH. The DMH influences feeding behavior by modulating the activity of different neurotransmitters in the brain. This nucleus receives both orexigenic and anorexic inputs through neural connections with the ARC and other regions of the brain. Due to its location in the brain, the ARC has access to nutritional inputs from the circulation. Within this nucleus, there exist two distinct neuronal populations, namely NPY and POMC. Different inputs from circulation affect two neuronal populations in the ARC. These inputs are related to second-order neurons, including DMH. The DMH integrates these inputs and sends the final output to PVN and LHA. Therefore, DMH affects the central control of feeding regulation through these neural pathways.

Alzheimer’s disease (AD) remains a significant health challenge, with an increasing prevalence globally. Recent research has aimed to deepen the understanding of the disease pathophysiology and to find potential therapeutic interventions. In this regard, G protein-coupled receptors (GPCRs) have emerged as novel potential therapeutic targets to palliate the progression of neurodegenerative diseases such as AD. Orexin and cannabinoid receptors are GPCRs capable of forming heteromeric complexes with a relevant role in the development of this disease. On the one hand, the hyperactivation of the orexins system has been associated with sleep–wake cycle disruption and Aβ peptide accumulation. On the other hand, cannabinoid receptor overexpression takes place in a neuroinflammatory environment, favoring neuroprotective effects. Considering the high number of interactions between cannabinoid and orexin systems that have been described, regulation of this interplay emerges as a new focus of research. In fact, in microglial primary cultures of APPSw/Ind mice model of AD there is an important increase in CB2R–OX1R complex expression, while OX1R antagonism potentiates the neuroprotective effects of CB2R. Specifically, pretreatment with the OX1R antagonist has been shown to strongly potentiate CB2R signaling in the cAMP pathway. Furthermore, the blockade of OX1R can also abolish the detrimental effects of OX1R overactivation in AD. In this sense, CB2R–OX1R becomes a new potential therapeutic target to combat AD.

Frailty, is a geriatric syndrome that reduces the resistance to stress situations caused by activities of daily living and increases morbidity and mortality. We hypothesized that a decrease in orexigenic peptides or an increase in anorexigenic peptides might be associated with frailty. We aimed to investigate the relationship between frailty and six appetite-related peptides: ghrelin, neuropeptide Y (NPY), agouti-related peptide (AgRP), cocaine-amphetamine-associated peptide (CART), peptide YY, and alpha MSH (α-MSH). This cross-sectional study was conducted on 85 older adults who visited the outpatient clinic. All patients underwent comprehensive geriatric assessment. Frailty status was assessed using the Fried frailty index. Plasma levels of six appetite-related peptides were studied. The mean age was 73.7 ± 5.4 years, 27 (31.8%) of the patients were male, and 32 of the patients (37.6%) were frail. While plasma levels of ghrelin, NPY and AgRP were significantly lower in frail patients, CART and α-MSH levels were higher compared to non-frail patients (p <.05 for all). Peptide YY was found to be higher in the frail group, however, the difference did not reach statistical significance (p =.052). In multivariate logistic regression analysis, the ghrelin, AgRP, CART, and α-MSH levels were independent predictors of frailty. Moreover, a weak correlation was found between all peptides(except NPY) and handgrip strength and Lawton-Brody score. Ghrelin, AgRP, CART, and α-MSH levels were found to be independent predictors of frailty. Our results suggest that appetite-related peptides might be playing roles in the pathogenesis of frailty. Further larger prospective studies are needed to test this hypothesis. [ABSTRACT FROM AUTHOR]

In living organisms, the central control of nutrition is a highly complex and vital mechanism. Central control of nutrition occurs in various regions of the brain, with the hypothalamus being the most important of which is the hypothalamus. The hypothalamus controls feeding behaviors through neural circuits, specialized nuclei, and central neurotransmitters. Different hypothalamic nuclei involved in regulating food intake include ARC, PVN, LHA, VMH, and DMH. The DMH influences feeding behavior by modulating the activity of different neurotransmitters in the brain. This nucleus receives both orexigenic and anorexic inputs through neural connections with the ARC and other regions of the brain. Due to its location in the brain, the ARC has access to nutritional inputs from the circulation. Within this nucleus, there exist two distinct neuronal populations, namely NPY and POMC. Different inputs from circulation affect two neuronal populations in the ARC. These inputs are related to second-order neurons, including DMH. The DMH integrates these inputs and sends the final output to PVN and LHA. Therefore, DMH affects the central control of feeding regulation through these neural pathways. [ABSTRACT FROM AUTHOR]

Neuronal circuits regulating appetite are dominated by arcuate nucleus neurons, which include appetite-promoting and -suppressing neurons that release the orexigenic neuropeptide agouti-related protein (AgRP) and anorexigenic neuropeptide pro-opiomelanocortin, respectively, to compete for melanocortin receptors to modulate feeding behavior. In this study, we expressed novel agrp promoters, including different lengths of the 5' flanking regions of the agrp gene (4749 bp) in the zebrafish genome. We used the agrp promoter to derive the enhanced green fluorescent protein (EGFP)-nitroreductase (NTR) fusion protein, allowing expression of the green fluorescence signal in the AgRP neurons. Then, we treated the transgenic zebrafish AgRP4.7NTR (Tg [agrp-EGFP-NTR]) with metronidazole to ablate the AgRP neurons in the larvae stage and observed a decline in their appetite and growth. The expression of most orexigenic and growth hormone/insulin-like growth factor axis genes decreased, whereas that of several anorexigenic genes increased. Our findings demonstrate that AgRP is a critical regulator of neuronal signaling for zebrafish appetite and energy intake control. Thus, AgRP4.7NTR can be used as a drug-screening platform for therapeutic targets to treat human appetite disorders, including obesity. Furthermore, the unique agrp promoter we identified can be a powerful tool for research on AgRP neurons, especially AgRP neuron-mediated pathways in the hypothalamus, and appetite. [ABSTRACT FROM AUTHOR]

Simple Summary: The effect of feeding and feed deprivation on the regulation of feed intake in European seabass was evaluated. European seabass possess feed intake regulation mechanisms similar to those found in mammals and fish. Fasting and feeding conditions induce different responses in feed intake regulation mechanisms in European seabass. The present results are important to identify and understand the mechanisms of appetite regulation of European seabass, and therefore contribute to feeding optimization processes, ensuring the growth and sustainability of the aquaculture industry. The present study aimed to evaluate the effects of feeding or feed deprivation on the orexigenic and anorexigenic responses at the central (whole brain) and peripheral (anterior and posterior intestine, stomach, and liver) system levels in European seabass. For this purpose, a group of fish (208 g) was fed a single meal daily for 8 days (fed group) and another group was feed-deprived for 8 days (unfed group). Compared to the fed group, in the whole brain, feed deprivation did not induce changes in npy, agrp1, and cart2 expression, but increased agrp2 and pomc1 expression. In the anterior intestine, feed deprivation increased cck expression, while in the posterior intestine, the npy expression increased and pyyb decreased. In the stomach, the ghr expression decreased regardless of the feeding status. The hepatic lep expression increased in the unfed fish. The present results suggest a feed intake regulation mechanism in European seabass similar to that observed in other teleosts. [ABSTRACT FROM AUTHOR]

This was a preliminary study that examined whether appetite regulation is altered during the menstrual cycle or with oral contraceptives. Ten naturally cycling females (NON-USERS) and nine tri-phasic oral contraceptive using females (USERS) completed experimental sessions during each menstrual phase (follicular phase: FP; ovulatory phase: OP; luteal phase: LP). Appetite perceptions and blood samples were obtained fasted, 30, 60, and 90 min post-prandial to measure acylated ghrelin, active glucagon-like peptide-1 (GLP-1), and total peptide tyrosine tyrosine (PYY). Changes were considered important if p < 0.100 and the effect size was ≥medium. There appeared to be a three-way (group x phase x time) interaction for acylated ghrelin where concentrations appeared to be greater in USERS versus NON-USERS during the OP 90-min post-prandial and during the LP fasted, and 90-min post-prandial. In USERS, ghrelin appeared to be greater 90-min post-prandial in the OP versus the FP with no other apparent differences between phases. There were no apparent differences between phases in NON-USERS. There appeared to be a three-way interaction for PYY where concentrations appeared to be greater in USERS during the FP 60-min post-prandial and during the OP 30-min post-prandial. In USERS PYY appeared to be greater 60-min post-prandial during the OP versus the LP with no other apparent differences. There were no apparent differences between phases in NON-USERS. There appeared to be no effect of group or phase on GLP-1, or appetite perceptions. These data demonstrate small effects of menstrual cycle phase and oral contraceptive use on the acylated ghrelin and total PYY response to a standardized meal, with no effects on active GLP-1 or perceived appetite, though more work with a large sample size is necessary. [ABSTRACT FROM AUTHOR]

Several mechanisms both inside and outside the central nervous system (CNS) collaborate to control feeding. The hypothalamus received food-related messages from different regions of the brain, and exports appropriate output through specific hypothalamic nuclei. One of the most important of these hypothalamic nuclei is the lateral hypothalamus area (LHA). In this review, multiple valid papers from electronic sources (including Web of Science, Scopus, PubMed, SID, Google Scholar, and ISI databases) were used; which in them the role of LHA in the central regulation of feeding investigated. The hypothalamus is responsible for the central control of food intake in the CNS. The arcuate nucleus, paraventricular nucleus, and LHA are specific regions in the hypothalamus that regulate food intake. The LHA is considered to be the center of hunger or feeding among these nuclei. With the interaction of orexigenic and anorexigenic neurons, as well as various neurotransmitters in several neuronal pathways, this nucleus produces increased food intake. The LHA eventually improved food intake via extensive brain connections. The LHA via various neurons and synaptic connections with other special hypothalamic nuclei involved in the control of nutritional behavior (graphical abstract) stimulated food intake. [ABSTRACT FROM AUTHOR]

Introduction: Neuropeptide Y (NPY) signaling in the brain plays an important role in energy regulation, and is altered during diet-induced obesity. Yet, NPY function during the consumption of specific diet components remains to be fully determined. We have previously demonstrated that consumption of a saturated fat component (free-choice high-fat; fcHF), a sucrose solution (high-sugar; fcHS), or both (fcHFHS) combined with a standard diet (chow and water) has diverse effects on Npy expression in the arcuate nucleus and the sensitivity to intraventricular NPY administration. Arcuate NPY neurons project to the lateral hypothalamus (LHA), and NPY administration in the LHA potently promotes chow intake in rats on a standard diet. However, it is currently unclear if short-term consumption of a palatable free-choice diet alters NPY function in the LHA. Therefore, we assessed the effects of intra-LHA NPY administration on intake in rats following one-week consumption of a fcHF, fcHS, or fcHFHS diet. Methods: Male Wistar rats consumed a fcHF, fcHS, fcHFHS, or control (CHOW) diet for one week before NPY (0.3 μg / 0.3 μL) or phosphate-buffered saline (0.3 μL) was administered into the LHA. Intake was measured 2h later. fcHFHS-fed rats were divided into high-fat (fcHFHS-hf) and low-fat (fcHFHS-lf) groups based on differences in basal fat intake. Results: Intra-LHA NPY administration increased chow intake in fcHFHS- (irrespective of basal fat intake), fcHF- and CHOW-fed rats. Intra-LHA NPY infusion increased fat intake in fcHF-, fcHFHS-hf, but not fcHFHS-lf, rats. Intra-LHA NPY infusion did not increase caloric intake in fcHS-fed rats. Discussion: Our data demonstrate that the effects of intra-LHA NPY on caloric intake differ depending on the consumption of a fat or sugar component, or both, in a free-choice diet. Our data also indicate that baseline preference for the fat diet component modulates the effects of intra-LHA NPY in fcHFHS-fed rats. [ABSTRACT FROM AUTHOR]

Feed is one of the most important external signals in fish that stimulates its feeding behavior and growth. The intake of feed is the main factor determining efficiency and cost, maximizing production efficiency in a fish farming firm. The physiological mechanism regulating food intake lies between an intricate connection linking central and peripheral signals that are unified in the hypothalamus consequently responding to the release of appetite-regulating genes that eventually induce or hinder appetite, such as apelin; a recently discovered peptide produced by several tissues with diverse physiological actions mediated by its receptor, such as feed regulation. Extrinsic factors have a great influence on food intake and feeding behavior in fish. Under these factors, feeding in fish is decontrolled and the appetite indicators in the brain do not function appropriately thus, in controlling conditions which result in the fluctuations in the expression of these appetite-relating genes, which in turn decrease food consumption. Here, we examine the research advancements in fish feeding behavior regarding dietary selection and preference and identify some key external influences on feed intake and feeding behavior. Also, we present summaries of the results of research findings on apelin as an appetite-regulating hormone in fish. We also identified gaps in knowledge and directions for future research to fully ascertain the functional importance of apelin in fish. [ABSTRACT FROM AUTHOR]

There is evidence of ghrelinergic-cannabinoidergic interactions in the central nervous system (CNS) that may impact on the plasticity of reward circuits. The aim of this article was to look for molecular and/or functional interactions between cannabinoid CB1 and ghrelin GHS-R1a receptors. In a heterologous system and using the bioluminescence resonance energy transfer technique we show that human versions of cannabinoid CB1 and ghrelin GHS-R1a receptors may form macromolecular complexes. Such receptor heteromers have particular properties in terms of CB1/Gi-mediated signaling and in terms of GHS-R1a-Gq-mediated signaling. On the one hand, just co-expression of CB1R and GHS-R1a led to impairment of cannabinoid signaling. On the other hand, cannabinoids led to an increase in ghrelin-derived calcium mobilization that was stronger at low concentrations of the CB1 receptor agonist, arachidonyl-2'-chloroethylamide (ACEA). The expression of CB1-GHS-R1a receptor complexes in striatal neurons was confirmed by in situ proximity ligation imaging assays. Upregulation of CB1-GHS-R1a- receptor complexes was found in striatal neurons from siblings of pregnant female mice on a high-fat diet. Surprisingly, the expression was upregulated after treatment of neurons with ghrelin (200 nM) or with ACEA (100 nM). These results help to better understand the complexities underlying the functional interactions of neuromodulators in the reward areas of the brain. [ABSTRACT FROM AUTHOR]

Neuronal circuits regulating appetite are dominated by arcuate nucleus neurons, which include appetite-promoting and -suppressing neurons that release the orexigenic neuropeptide agouti-related protein (AgRP) and anorexigenic neuropeptide pro-opiomelanocortin, respectively, to compete for melanocortin receptors to modulate feeding behavior. In this study, we expressed novel agrp promoters, including different lengths of the 5’ flanking regions of the agrp gene (4749 bp) in the zebrafish genome. We used the agrp promoter to derive the enhanced green fluorescent protein (EGFP)-nitroreductase (NTR) fusion protein, allowing expression of the green fluorescence signal in the AgRP neurons. Then, we treated the transgenic zebrafish AgRP4.7NTR (Tg [agrp-EGFP-NTR]) with metronidazole to ablate the AgRP neurons in the larvae stage and observed a decline in their appetite and growth. The expression of most orexigenic and growth hormone/insulin-like growth factor axis genes decreased, whereas that of several anorexigenic genes increased. Our findings demonstrate that AgRP is a critical regulator of neuronal signaling for zebrafish appetite and energy intake control. Thus, AgRP4.7NTR can be used as a drug-screening platform for therapeutic targets to treat human appetite disorders, including obesity. Furthermore, the unique agrp promoter we identified can be a powerful tool for research on AgRP neurons, especially AgRP neuron-mediated pathways in the hypothalamus, and appetite.

There is evidence of ghrelinergic-cannabinoidergic interactions in the central nervous system (CNS) that may impact on the plasticity of reward circuits. The aim of this article was to look for molecular and/or functional interactions between cannabinoid CB1 and ghrelin GHS-R1a receptors. In a heterologous system and using the bioluminescence resonance energy transfer technique we show that human versions of cannabinoid CB1 and ghrelin GHS-R1a receptors may form macromolecular complexes. Such receptor heteromers have particular properties in terms of CB1/Gi-mediated signaling and in terms of GHS-R1a-Gq-mediated signaling. On the one hand, just co-expression of CB1R and GHS-R1a led to impairment of cannabinoid signaling. On the other hand, cannabinoids led to an increase in ghrelin-derived calcium mobilization that was stronger at low concentrations of the CB1 receptor agonist, arachidonyl-2’-chloroethylamide (ACEA). The expression of CB1-GHS-R1a receptor complexes in striatal neurons was confirmed by in situ proximity ligation imaging assays. Upregulation of CB1-GHS-R1a- receptor complexes was found in striatal neurons from siblings of pregnant female mice on a high-fat diet. Surprisingly, the expression was upregulated after treatment of neurons with ghrelin (200 nM) or with ACEA (100 nM). These results help to better understand the complexities underlying the functional interactions of neuromodulators in the reward areas of the brain.

Feed is one of the most important external signals in fish that stimulates its feeding behavior and growth. The intake of feed is the main factor determining efficiency and cost, maximizing production efficiency in a fish farming firm. The physiological mechanism regulating food intake lies between an intricate connection linking central and peripheral signals that are unified in the hypothalamus consequently responding to the release of appetite-regulating genes that eventually induce or hinder appetite, such as apelin; a recently discovered peptide produced by several tissues with diverse physiological actions mediated by its receptor, such as feed regulation. Extrinsic factors have a great influence on food intake and feeding behavior in fish. Under these factors, feeding in fish is decontrolled and the appetite indicators in the brain do not function appropriately thus, in controlling conditions which result in the fluctuations in the expression of these appetite-relating genes, which in turn decrease food consumption. Here, we examine the research advancements in fish feeding behavior regarding dietary selection and preference and identify some key external influences on feed intake and feeding behavior. Also, we present summaries of the results of research findings on apelin as an appetite-regulating hormone in fish. We also identified gaps in knowledge and directions for future research to fully ascertain the functional importance of apelin in fish.

Plants with diverse pharmacological activities are actively being explored for human health. Cissus quadrangularis (L) has been reported to possess numerous phytochemicals and is used to relieve various disorders. The aim of the present study was to provide evidence of the diverse pharmacological activities in terms of orexigenic, anti-inflammatory, anti-diabetic and antioxidant activities of C. quadrangularis for further application in clinical development. The results revealed that inhibition of hemolysis was within the range of 8-9-25.6% at concentrations of 12.5-200 μg/ml. Methanol extract of the stems exhibited porcine pancreatic α-amylase (PPA) inhibition (p≤0.05) at concentrations of 0.25 and 0.30 mg/ml. The glucose adsorption capacity of the plant was observed to be inversely proportional to the molar concentration of glucose. The higher food intake by Drosophila in food medium with plant extract was presumably related to the orexigenic property of C. quadrangularis. Protease activity of the stem extract revealed total activity 975 U/ml and specific activity as 3768 U/mg. The absorbance of the plant in reducing power assay was between 0.91and 1.85. The highest total antioxidant activity of 67.2 μg TE/g was observed and the hydroxyl radicals scavenging activity was observed in a dose-dependent manner. The results provided supporting data that C. quadrangularis may contain active compounds useful in treating anti-inflammatory, anti-diabetic disorders. [ABSTRACT FROM AUTHOR]

Objectives: Cyproheptadine is a first-generation H1-antihistamine drug first that was distributed in the 1960s. While its orexigenic effect was observed early, cyproheptadine is not yet authorized for this indication in all countries today. There is an increasing medical interest and demand for the orexigenic effect of cyproheptadine, especially in children with poor appetite. As cyproheptadine might be evaluated in future clinical trials, we wanted to assess its safety profile.Methods: Using the French national pharmacovigilance database, we retrospectively analyzed all pediatric and adult reports of adverse effects of cyproheptadine recorded since its first distribution in France. Next, we performed a systematic review of the literature of cyproheptadine adverse effects.Results: Since 1985, 93 adverse effects were reported in the French pharmacovigilance database (adults 81.7%, children 18.3%); these were mainly neurological symptoms (n = 38, adults 71%, children 28.9%), and hepatic complications (n = 15, adults 86.7%, children 13.3%). In the literature, the most frequent adverse effect reported was drowsiness in adults or children, and five case reports noted liver complications in adults. We estimated the frequency of hepatic adverse effects at 0.27 to 1.4/1000, regardless of age.Conclusion: Cyproheptadine can be considered a safe drug. Mild neurological effects appear to be frequent, and hepatotoxicity is uncommon to rare. Randomized controlled trials are needed to evaluate the safety and efficacy of cyproheptadine before authorization for appetite stimulation, especially in young children as studies at this age are lacking. Possible hepatic complications should be monitored, as very rare cases of liver failure have been reported.

The present study aimed to evaluate the effects of feeding or feed deprivation on the orexigenic and anorexigenic responses at the central (whole brain) and peripheral (anterior and posterior intestine, stomach, and liver) system levels in European seabass. For this purpose, a group of fish (208 g) was fed a single meal daily for 8 days (fed group) and another group was feed-deprived for 8 days (unfed group). Compared to the fed group, in the whole brain, feed deprivation did not induce changes in npy, agrp1, and cart2 expression, but increased agrp2 and pomc1 expression. In the anterior intestine, feed deprivation increased cck expression, while in the posterior intestine, the npy expression increased and pyyb decreased. In the stomach, the ghr expression decreased regardless of the feeding status. The hepatic lep expression increased in the unfed fish. The present results suggest a feed intake regulation mechanism in European seabass similar to that observed in other teleosts.

The influence of Artificial Light at Night (ALAN) is a severe interference in the biological rhythm of organisms. Feeding dysregulation might be the main factor responsible for developing metabolic diseases. The molecular basis of these physiological dysregulations is yet to be elucidated. The effect of light on appetite-regulating signal in the brain of zebrafish is still unknown. Therefore, the present study aimed to find the daily mRNA expression profile of two significant appetite and energy-balancing peptide hormone (leptin) and enzyme (goat) in the brain in various illumination conditions, LD (12Light:12Dark), LL (24L), and DD (24D). Moreover, Ga-SI, the protein level of the two appetite-regulating peptides, and brain and serum melatonin are measured after 72 h of incubation under three different photic conditions. The immunohistochemical localization of the primary mediators of appetite regulators, leptin and goat, in the brain of zebrafish, under different photic conditions, is reported for the first time in zebrafish. The study revealed that in continuous light after 72 h of incubation, feeding (Ga-SI) is found the highest and the translational level of two appetite-related genes (leptin and goat) is the lowest compared to LD. In continuous dark, this relation becomes opposite. The daily variation of mRNA expression of leptin and goat in LD shows peak expression at the light and dark phase, respectively. This pattern was abolished in continuous conditions. Thus, our study suggests that the photoperiod (zeitgeber) may influence the expression pattern (daily variation) of appetite-regulating peptide hormone and enzyme in the brain of zebrafish.

Ghrelin has garnered interest as a gut-derived regulator of lipid metabolism, beyond its classical roles in driving appetite and growth hormone release. Ghrelin’s circulating concentrations follow an ultradian rhythm, peak immediately before a meal and point towards a potential metabolic role in reducing the mobilization of fatty acid stores in preparation for the storage of ingested food. Here, we demonstrate that both acylated and unacylated ghrelin have physiological roles in attenuating lipolysis in mature subcutaneous and visceral adipose tissue depots of rats. Ghrelin blunted the ß3-induction (CL 316, 243) of glycerol release (index of lipolysis) which coincided with a reduced activation of the key lipid hydrolase HSL at two of its serine residues (Ser563/660). Furthermore, ghrelin appeared to inhibit fatty acid reesterification in the presence of CL such that fatty acid concentrations in the surrounding media were maintained in spite of a reduction in lipolysis. Importantly, these aforementioned effects were not observed following ghrelin injection in vivo, as there was no attenuation of CL-induced glycerol release. This highlights the importance of exercising caution when interpreting the effects of administering ghrelin in vivo, and the necessity for uncovering the elusive mechanisms by which ghrelin regulates lipolysis and fatty acid reesterification. We conclude that both acylated and unacylated ghrelin can exert direct inhibitory effects on lipolysis and fatty acid reesterification in adipose tissue from rats. However, these effects are not observed in vivo and outline the complexity of studying ghrelin’s effects on fatty acid metabolism in the living animal.

Purpose: The therapeutic utility of Cannabis in cancer is a topic of intense interest. Dronabinol is synthetic Δ9-tetrahydrocannabinol (THC), the primary psychoactive component of Cannabis sativa, and is approved for treating refractory chemotherapy-induced nausea and vomiting. Little is known about dronabinol prescribing in children and young adults, and no published concentration data are available. This study evaluated national level dronabinol use and assessed concentrations of THC and its primary metabolites in patients with cancer <27 years of age prescribed dronabinol. Methods: Observational review of records from the Pediatric Health Information System (PHIS) and a regional network of hospitals in the Intermountain West, including a tertiary care children's hospital, Primary Children's Hospital (PCH), for inpatients <27 years of age prescribed dronabinol. Prospective blood samples were collected from children with cancer at PCH. Results: Across PHIS institutions, overall dronabinol prescribing aligned with the pharmacy records for those with cancer (p < 0.0001), and of these, 10.4% received dronabinol as inpatients. Blood collected within 72 hours of dronabinol administration was available from 10 children with a median age of 12.5 (range 6–17) years. Quantifiable concentrations were found in 4 (13%), 6 (20%), and 1 (3%) samples assayed for THC, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (COOH-THC), and 11-hydroxy-Δ9-tetrahydrocannabinol (OH-THC), respectively. THC concentrations ranged between 0.100 and 0.128 ng/mL and were not associated with dose. Conclusion: Dronabinol prescribing appears exclusive to patients diagnosed with cancer, and its use has increased steadily in the past decade. In a small sample of children administered dronabinol, THC and metabolite concentrations were consistently low or undetectable. [ABSTRACT FROM AUTHOR]

Cachexia is a devastating complication of cancer and an important cause of morbidity and mortality and can have a great effect on quality of life, and sense of self-esteem. Unfortunately; there is no standard cure available for cancer cachexia. Ghrelin; a 28 amino acid orexigenic gut hormone and its mimetics have shown potential benefits in reversing the breakdown of protein and weight loss in catabolic states like cancer cachexia. Ghrelin has effects on several vital pathways in the regulation of appetite, and composition of the body. It increases the secretion of growth hormone and reduces energy expenditure. It plays an important role in regulation of processes associated with cancer and antagonizing protein breakdown in catabolic conditions such as cancer cachexia. Additionally, ghrelin has anti-inflammatory, anti-apoptotic and anxiolytic effects. Administration of ghrelin for short-term has been found to be well-tolerated and safe. These versatile actions of ghrelin and its safety can render it as a potentially useful novel therapy for patients with cancer cachexia. However; there is a need to generate more evidence to support the use of ghrelin in the management of cancer cachexia.

High-intensity exercise inhibits appetite, in part, via alterations in the peripheral concentrations of the appetite-regulating hormones acylated ghrelin, active glucagon-like peptide-1 (GLP-1), and active peptide tyrosine-tyrosine (PYY). Given lactate may mediate these effects, we used sodium bicarbonate (NaHCO3) supplementation in a double-blind, placebo-controlled, crossover design to investigate lactate’s purported role in exercise-induced appetite suppression. Eleven males completed two identical high-intensity interval training sessions (10 × 1 min cycling bouts at ~90% heart rate maximum interspersed with 1-min recovery), where they ingested either NaHCO3 (BICARB) or sodium chloride (NaCl) as a placebo (PLACEBO) preexercise. Blood lactate, acylated ghrelin, GLP-1, and PYY concentrations, as well as overall appetite were assessed preexercise and 0, 30, 60, and 90 min postexercise. Blood lactate was greater immediately (P < 0.001) and 30 min postexercise (P = 0.049) in the BICARB session with an increased (P = 0.009) area under the curve (AUC). The BICARB session had lower acylated ghrelin at 60 (P = 0.014) and 90 min postexercise (P = 0.016), with a decreased AUC (P = 0.039). The BICARB session had increased PYY (P = 0.034) with an increased AUC (P = 0.031). The BICARB session also tended (P = 0.060) to have increased GLP-1 at 30 (P = 0.003) and 60 min postexercise (P < 0.001), with an increased AUC (P = 0.030). The BICARB session tended (P = 0.059) to reduce overall appetite, although there was no difference in AUC (P = 0.149). These findings support a potential role for lactate in the high-intensity exercise-induced appetite-suppression. NEW & NOTEWORTHY We used sodium bicarbonate to increase lactate accumulation or sodium chloride as a placebo. Our findings further implicate lactate as a mediator of exercise-induced appetite suppression, given exercise-induced increases in lactate during the sodium bicarbonate session altered peripheral concentrations of appetite-regulating hormones, culminating in a reduction of appetite. This supports a lactate-dependent mechanism of appetite suppression following high-intensity exercise and highlights the potential of using lactate as a means of inducing a caloric deficit. [ABSTRACT FROM AUTHOR]

Feeding is a complex behaviour comprised of satiety control, foraging, ingestion and subsequent digestion. Cichlids from the East African Great Lakes are renowned for their diverse trophic specializations, largely predicated on highly variable jaw morphologies. Thus, most research has focused on dissecting the genetic, morphological and regulatory basis of jaw and teeth development in these species. Here for the first time we explore another aspect of feeding, the regulation of appetite related genes that are expressed in the brain and control satiety in cichlid fishes. Using qPCR analysis, we first validate stably expressed reference genes in the brain of six haplochromine cichlid species at the end of larval development prior to foraging. We next evaluate the expression of 16 appetite related genes in herbivorous and carnivorous species from the parallel radiations of Lake Tanganyika, Malawi and Victoria. Interestingly, we find increased expression of two appetite-regulating genes (anorexigenic genes), cart and npy2r, in the brain of carnivorous species in all the three lakes. This supports the notion that appetite gene regulation might play a part in determining trophic niche specialization in divergent cichlid species, already prior to exposure to different diets. Our study contributes to the limited body of knowledge on the neurological circuitry that controls feeding transitions and adaptations in cichlids and other teleosts. [ABSTRACT FROM AUTHOR]

Ghrelin has garnered interest as a gut-derived regulator of lipid metabolism, beyond its classical roles in driving appetite and growth hormone release. Ghrelin's circulating concentrations follow an ultradian rhythm, peak immediately before a meal and point towards a potential metabolic role in reducing the mobilization of fatty acid stores in preparation for the storage of ingested food. Here, we demonstrate that both acylated and unacylated ghrelin have physiological roles in attenuating lipolysis in mature subcutaneous and visceral adipose tissue depots of rats. Ghrelin blunted the ß3-induction (CL 316, 243) of glycerol release (index of lipolysis) which coincided with a reduced activation of the key lipid hydrolase HSL at two of its serine residues (Ser563/660). Furthermore, ghrelin appeared to inhibit fatty acid reesterification in the presence of CL such that fatty acid concentrations in the surrounding media were maintained in spite of a reduction in lipolysis. Importantly, these aforementioned effects were not observed following ghrelin injection in vivo, as there was no attenuation of CL-induced glycerol release. This highlights the importance of exercising caution when interpreting the effects of administering ghrelin in vivo, and the necessity for uncovering the elusive mechanisms by which ghrelin regulates lipolysis and fatty acid reesterification. We conclude that both acylated and unacylated ghrelin can exert direct inhibitory effects on lipolysis and fatty acid reesterification in adipose tissue from rats. However, these effects are not observed in vivo and outline the complexity of studying ghrelin's effects on fatty acid metabolism in the living animal. [ABSTRACT FROM AUTHOR]

Cannabinoids have been reported as orexigenic, i.e., as promoting food intake that, among others, is controlled by the so-called “hunger” hormone, ghrelin. The aim of this paper was to look for functional and/or molecular interactions between ghrelin GHSR1a and cannabinoid CB2 receptors at the central nervous system (CNS) level. In a heterologous system we identified CB2-GHSR1a receptor complexes with a particular heteromer print consisting of impairment of CB2 receptor/Gi-mediated signaling. The blockade was due to allosteric interactions within the heteromeric complex as it was reverted by antagonists of the GHSR1a receptor. Cannabinoids acting on the CB2 receptor did not affect cytosolic increases of calcium ions induced by ghrelin acting on the GHSR1a receptor. In situ proximity ligation imaging assays confirmed the expression of CB2-GHSR1a receptor complexes in both heterologous cells and primary striatal neurons. We tested heteromer expression in neurons from offspring of high-fat-diet mouse mothers as they have more risk to be obese. Interestingly, there was a marked upregulation of those complexes in striatal neurons from siblings of pregnant female mice under a high-fat diet.

Neuropeptide Y family (NPY) is a potent orexigenic peptide and pancreatic polypeptide family comprising neuropeptide Y (Npy), peptide YYa (Pyya), and peptide YYb (Pyyb), which was previously known as peptide Y (PY), and tetrapod pancreatic polypeptide (PP), but has not been exhaustively documented in fish. Nonetheless, Npy and Pyy to date have been the key focus of countless research studies categorizing their copious characteristics in the body, which, among other things, include the mechanism of feeding behavior, cortical neural activity, heart activity, and the regulation of emotions in teleost. In this review, we focused on the role of neuropeptide Y gene (Npy) and peptide YY gene (Pyy) in teleost food intake. Feeding is essential in fish to ensure growth and perpetuation, being indispensable in the aquaculture settings where growth is prioritized. Therefore, a better understanding of the roles of these genes in food intake in teleost could help determine their feeding regime, regulation, growth, and development, which will possibly be fundamental in fish culture.

Ghrelin is an endogenous peptide hormone mainly produced in the stomach. It has been known to regulate energy homeostasis, stimulate secretion of growth hormone, and mediate many other physiologic effects. Various effects attributed to ghrelin contribute to many aspects of cancer development and progression. Accordingly, a large body of evidence has emerged about the association of ghrelin with several types of cancer in scales of cell-line, animal, and human studies. However, existing data are controversial. This controversy occurs in two main domains: one is the controversial results in local effects of ghrelin on different types of human cancer cell-lines; the second is the apparent disagreement in the results of in-vitro and clinical studies that investigated ghrelin association to one type of cancer. These inconsistencies have hampered the indications to consider ghrelin as a potential tumor biomarker or therapeutic agent in cancer patients. Previous studies have reviewed different parts of current literature about the ghrelin-cancer relationship. Although they have highlighted these controversial results in various ways, no specific recommendations have been given to address it. In this study, we comprehensively reviewed in-vitro, in-vivo, and clinical studies and attempted to use the following approaches to unravel the inconsistencies detected: (a) to distinguish local and systemic effects of ghrelin in interpreting its summary clinical role in each cancer; (b) scrutinizing factors that regulate local effects of ghrelin and could justify different effects of ghrelin on different cancer cell-lines. These approaches could have notable implications for future in-vitro and clinical studies.

Ghrelin is an endogenous peptide hormone mainly produced in the stomach. It has been known to regulate energy homeostasis, stimulate secretion of growth hormone, and mediate many other physiologic effects. Various effects attributed to ghrelin contribute to many aspects of cancer development and progression. Accordingly, a large body of evidence has emerged about the association of ghrelin with several types of cancer in scales of cell-line, animal, and human studies. However, existing data are controversial. This controversy occurs in two main domains: one is the controversial results in local effects of ghrelin on different types of human cancer cell-lines; the second is the apparent disagreement in the results of in-vitro and clinical studies that investigated ghrelin association to one type of cancer. These inconsistencies have hampered the indications to consider ghrelin as a potential tumor biomarker or therapeutic agent in cancer patients. Previous studies have reviewed different parts of current literature about the ghrelin-cancer relationship. Although they have highlighted these controversial results in various ways, no specific recommendations have been given to address it. In this study, we comprehensively reviewed in-vitro, in-vivo , and clinical studies and attempted to use the following approaches to unravel the inconsistencies detected: (a) to distinguish local and systemic effects of ghrelin in interpreting its summary clinical role in each cancer; (b) scrutinizing factors that regulate local effects of ghrelin and could justify different effects of ghrelin on different cancer cell-lines. These approaches could have notable implications for future in-vitro and clinical studies. [ABSTRACT FROM AUTHOR]

Key points: Excitatory glutamate neurons are sparse in the rostral hypothalamic arcuate nucleus (ARC), the subregion that has received the most attention in the past. In striking contrast, excitatory neurons are far more common (by a factor of 10) in the caudal ARC, an area which has received relatively little attention.These glutamate cells may play a negative role in energy balance and food intake. They can show an increase in phosphorylated Stat‐3 in the presence of leptin, are electrically excited by the anorectic neuromodulator cholecystokinin, and inhibited by orexigenic neuromodulators neuropeptide Y, met‐enkephalin, dynorphin and the catecholamine dopamine.The neurons project local axonal connections that excite other ARC neurons including proopiomelanocortin neurons that can play an important role in obesity.These data are consistent with models suggesting that the ARC glutamatergic neurons may play both a rapid and a slower role in acting as anorectic neurons in CNS control of food intake and energy homeostasis. Here we interrogate a unique class of excitatory neurons in the hypothalamic arcuate nucleus (ARC) that utilizes glutamate as a fast neurotransmitter using mice expressing GFP under control of the vesicular glutamate transporter 2 (vGluT2) promoter. These neurons show a unique distribution, synaptic characterization, cellular physiology and response to neuropeptides involved in energy homeostasis. Although apparently not previously appreciated, the caudal ARC showed a far greater density of vGluT2 cells than the rostral ARC, as seen in transgenic vGluT2‐GFP mice and mRNA analysis. After food deprivation, leptin induced an increase in phosphorylated Stat‐3 in vGluT2‐positive neurons, indicating a response to hormonal cues of energy state. Based on whole‐cell recording electrophysiology in brain slices, vGluT2 neurons were spontaneously active with a spike frequency around 2 Hz. vGluT2 cells were responsive to a number of neuropeptides related to energy homeostasis; they were excited by the anorectic peptide cholecystokinin, but inhibited by orexigenic neuropeptide Y, dynorphin and met‐enkephalin, consistent with an anorexic role in energy homeostasis. Dopamine, associated with the hedonic aspect of enhancing food intake, inhibited vGluT2 neurons. Optogenetic excitation of vGluT2 cells evoked EPSCs in neighbouring neurons, indicating local synaptic excitation of other ARC neurons. Microdrop excitation of ARC glutamate cells in brain slices rapidly increased excitatory synaptic activity in anorexigenic proopiomelanocortin neurons. Together these data support the perspective that vGluT2 cells may be more prevalent in the ARC than previously appreciated, and play predominantly an anorectic role in energy metabolism. Key points: Excitatory glutamate neurons are sparse in the rostral hypothalamic arcuate nucleus (ARC), the subregion that has received the most attention in the past. In striking contrast, excitatory neurons are far more common (by a factor of 10) in the caudal ARC, an area which has received relatively little attention.These glutamate cells may play a negative role in energy balance and food intake. They can show an increase in phosphorylated Stat‐3 in the presence of leptin, are electrically excited by the anorectic neuromodulator cholecystokinin, and inhibited by orexigenic neuromodulators neuropeptide Y, met‐enkephalin, dynorphin and the catecholamine dopamine.The neurons project local axonal connections that excite other ARC neurons including proopiomelanocortin neurons that can play an important role in obesity.These data are consistent with models suggesting that the ARC glutamatergic neurons may play both a rapid and a slower role in acting as anorectic neurons in CNS control of food intake and energy homeostasis. [ABSTRACT FROM AUTHOR]