Leptin enhances feeding suppression and neural activation produced by systemically administered bombesin

2005 ◽  
Vol 289 (2) ◽  
pp. R473-R477 ◽  
Author(s):  
Ellen E. Ladenheim ◽  
M. Emond ◽  
T. H. Moran
Keyword(s):  
Food Intake ◽  
Fold Increase ◽  
Liquid Diet ◽  
Individual Response ◽  
Neural Activation ◽  
Solitary Tract ◽  
Significant Suppression ◽  
Feeding Inhibition ◽  
Feeding Suppression ◽  
The Individual

Leptin amplifies feeding inhibition and neural activation produced by either cholecystokinin or intragastric preloads, suggesting that leptin may increase the efficacy of gastrointestinal meal-related signals. To determine whether leptin would similarly potentiate the feeding inhibitory actions of another putative satiety peptide, we evaluated the effects of third ventricular leptin administration on food intake and c-Fos activation in response to systemically administered bombesin (BN). Leptin (3.5 μg) was administered 1 h before either 0.9% saline or BN (0.32 and 1.0 nmol/kg) followed by 30-min access to Ensure liquid diet. Although neither leptin nor 0.32 nmol/kg BN alone suppressed Ensure intake, the combination reduced intake by 28%. The higher BN dose (1.0 nmol/kg) produced a significant suppression by itself but was further enhanced in the presence of leptin. Consistent with the behavioral results, c-Fos activation in the nucleus of the solitary tract was increased by combined dosages of leptin and 0.32 nmol/kg BN beyond the individual response to either peptide. In the presence of leptin, BN produced a 3.4- to 5.2-fold increase in the number of c-Fos-positive cells in the nucleus of the solitary tract compared with when BN was given alone. These data provide further support for the hypothesis that the effect of leptin on food intake may be mediated, in part, by modulating meal-related satiety signals.

scholarly journals Hindbrain glucagon-like peptide-1 neurons track intake volume and contribute to injection stress-induced hypophagia in meal-entrained rats

2016 ◽  
Vol 310 (10) ◽  
pp. R906-R916 ◽  
Author(s):  
Alison D. Kreisler ◽  
Linda Rinaman
Keyword(s):  
Food Intake ◽  
Potential Role ◽  
Liquid Diet ◽  
Neural Activation ◽  
Intracerebroventricular Injection ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Diet Intake ◽  
Published Research ◽  
Diet Type

Published research supports a role for central glucagon-like peptide 1 (GLP-1) signaling in suppressing food intake in rodent species. However, it is unclear whether GLP-1 neurons track food intake and contribute to satiety, and/or whether GLP-1 signaling contributes to stress-induced hypophagia. To examine whether GLP-1 neurons track intake volume, rats were trained to consume liquid diet (LD) for 1 h daily until baseline intake stabilized. On test day, schedule-fed rats consumed unrestricted or limited volumes of LD or unrestricted volumes of diluted (calorically matched to LD) or undiluted Ensure. Rats were perfused after the test meal, and brains processed for immunolocalization of cFos and GLP-1. The large majority of GLP-1 neurons expressed cFos in rats that consumed satiating volumes, regardless of diet type, with GLP-1 activation proportional to intake volume. Since GLP-1 signaling may limit intake only when such large proportions of GLP-1 neurons are activated, a second experiment examined the effect of central GLP-1 receptor (R) antagonism on 2 h intake in schedule-fed rats. Compared with baseline, intracerebroventricular vehicle (saline) suppressed Ensure intake by ∼11%. Conversely, intracerebroventricular injection of vehicle containing GLP-1R antagonist increased intake by ∼14% compared with baseline, partly due to larger second meals. We conclude that GLP-1 neural activation effectively tracks liquid diet intake, that intracerebroventricular injection suppresses intake, and that central GLP-1 signaling contributes to this hypophagic effect. GLP-1 signaling also may contribute to satiety after large volumes have been consumed, but this potential role is difficult to separate from a role in the hypophagic response to intracerebroventricular injection.

Meal-related stimuli differentially induce c-Fos activation in the nucleus of the solitary tract

2001 ◽  
Vol 280 (5) ◽  
pp. R1315-R1321 ◽  
Author(s):  
Michael Emond ◽  
Gary J. Schwartz ◽  
Timothy H. Moran
Keyword(s):  
Gastrointestinal Tract ◽  
Oral Cavity ◽  
Area Postrema ◽  
Prior Experience ◽  
Liquid Diet ◽  
Neural Activation ◽  
Solitary Tract ◽  
Multiple Levels ◽  
Meal Ingestion ◽  
Upper Gastrointestinal

Feedback signals arising from the oral cavity and upper gastrointestinal tract contribute to the control of meal size. To assess how these signals are integrated at central sites involved in ingestive control, we compared levels of c-Fos activation in the nucleus of the solitary tract (NTS) and area postrema (AP) in response to meal ingestion or gastric and duodenal infusions in the rat. Ingestion of a liquid diet to satiety induced significant fos-like immunoreactivity (FLI) at multiple levels of the NTS and within the AP. The restriction of intake to one-half the normal ingestion of a rat did not result in significant FLI, although gastric infusion of this liquid diet volume did. Fast bolus infusion resulted in greater FLI than did the same volume infused at a rate to mimic that of normal ingestion. Prior experience with gastric infusions did not affect the amounts of FLI within the NTS or AP. In rats with pyloric cuffs blocking flow from the stomach to the intestine, combined gastric load and duodenal nutrient elicited significantly greater FLI than either gastric or duodenal infusions alone. These data demonstrate that neural activation arising from meal-related stimuli are integrated at the level of the NTS.

Central leptin modulates behavioral and neural responsivity to CCK

1999 ◽  
Vol 276 (5) ◽  
pp. R1545-R1549 ◽  
Author(s):  
Michael Emond ◽  
Gary J. Schwartz ◽  
Ellen E. Ladenheim ◽  
Timothy H. Moran
Keyword(s):  
Food Intake ◽  
Paraventricular Nucleus ◽  
Area Postrema ◽  
Protein Product ◽  
Liquid Diet ◽  
Solitary Tract ◽  
Ob Gene ◽  
Medial Nucleus

The mechanisms through which leptin, the protein product of the ob gene, affects food intake remain to be determined. To assess whether the actions of leptin depend on modulation of within-meal satiety signals, we measured the effect of third ventricular leptin administration on the satiety actions of CCK. Leptin (10 μg) administered 1 h before 30-min access to a liquid diet had no effect on intake when administered alone, but doses of 3.5 or 10 μg dose dependently increased the suppression of intake produced by 1 nmol/kg CCK. Examination of patterns of c-Fos activation induced by 3.5 μg leptin and 1 nmol/kg CCK revealed that the combination produced significant c-Fos activation within the area postrema and the caudal and medial nucleus of the solitary tract (NST) compared with either leptin or CCK treatments alone. The leptin-CCK combination also resulted in increased c-Fos activation within the paraventricular nucleus of the hypothalamus above that produced by leptin alone. These data suggest that the actions of leptin in food intake are mediated through its ability to modulate responsivity to within-meal satiety signals.

scholarly journals Spectral Pitch Similarity is a Predictor of Perceived Change in Sound- as Well as Note-Based Music

2019 ◽  
Vol 2 ◽  
pp. 205920431984735
Author(s):  
Roger T. Dean ◽  
Andrew J. Milne ◽  
Freya Bailes
Keyword(s):  
Time Series ◽  
Piano Music ◽  
Individual Response ◽  
Discrete Events ◽  
Acoustic Intensity ◽  
Spectral Parameters ◽  
Cross Sectional ◽  
Perceived Change ◽  
Predictive Role ◽  
The Individual

Spectral pitch similarity (SPS) is a measure of the similarity between spectra of any pair of sounds. It has proved powerful in predicting perceived stability and fit of notes and chords in various tonal and microtonal instrumental contexts, that is, with discrete tones whose spectra are harmonic or close to harmonic. Here we assess the possible contribution of SPS to listeners’ continuous perceptions of change in music with fewer discrete events and with noisy or profoundly inharmonic sounds, such as electroacoustic music. Previous studies have shown that time series of perception of change in a range of music can be reasonably represented by time series models, whose predictors comprise autoregression together with series representing acoustic intensity and, usually, the timbral parameter spectral flatness. Here, we study possible roles for SPS in such models of continuous perceptions of change in a range of both instrumental (note-based) and sound-based music (generally containing more noise and fewer discrete events). In the first analysis, perceived change in three pieces of electroacoustic and one of piano music is modeled, to assess the possible contribution of (de-noised) SPS in cooperation with acoustic intensity and spectral flatness series. In the second analysis, a broad range of nine pieces is studied in relation to the wider range of distinctive spectral predictors useful in previous perceptual work, together with intensity and SPS. The second analysis uses cross-sectional (mixed-effects) time series analysis to take advantage of all the individual response series in the dataset, and to assess the possible generality of a predictive role for SPS. SPS proves to be a useful feature, making a predictive contribution distinct from other spectral parameters. Because SPS is a psychoacoustic “bottom up” feature, it may have wide applicability across both the familiar and the unfamiliar in the music to which we are exposed.

LONG‐TIME RESPONSE PREDICTED BY EXACT ELASTIC RAY THEORY

Geophysics ◽  
1965 ◽  
Vol 30 (3) ◽  
pp. 363-368 ◽  
Author(s):  
T. W. Spencer
Keyword(s):  
Formal Solution ◽  
Intermediate Stage ◽  
Time Limit ◽  
Time Interval ◽  
Individual Response ◽  
Axially Symmetric ◽  
Long Time ◽  
The Difference ◽  
The Individual ◽  
Significant Figures

The formal solution for an axially symmetric radiation field in a multilayered, elastic system can be expanded in an infinite series. Each term in the series is associated with a particular raypath. It is shown that in the long‐time limit the individual response functions produced by a step input in particle velocity are given by polynomials in odd powers of the time. For rays which suffer m reflections, the degree of the polynomials is 2m+1. The total response is obtained by summing all rays which contribute in a specified time interval. When the rays are selected indiscriminately, the difference between the magnitude of the partial sum at an intermediate stage of computation and the magnitude of the correct total sum may be greater than the number of significant figures carried by the computer. A prescription is stated for arranging the rays into groups. Each group response function varies linearly in the long‐time limit and goes to zero when convolved with a physically realizable source function.

Individual variation in response to altitude training

1998 ◽  
Vol 85 (4) ◽  
pp. 1448-1456 ◽  
Author(s):  
Robert F. Chapman ◽  
James Stray-Gundersen ◽  
Benjamin D. Levine
Keyword(s):  
Cell Volume ◽  
Sea Level ◽  
Interval Training ◽  
Training Model ◽  
Individual Response ◽  
Altitude Training ◽  
Moderate Altitude ◽  
Red Cell ◽  
Red Cell Volume ◽  
The Individual

Moderate-altitude living (2,500 m), combined with low-altitude training (1,250 m) (i.e., live high-train low), results in a significantly greater improvement in maximal O2 uptake (V˙o 2 max) and performance over equivalent sea-level training. Although the mean improvement in group response with this “high-low” training model is clear, the individual response displays a wide variability. To determine the factors that contribute to this variability, 39 collegiate runners (27 men, 12 women) were retrospectively divided into responders ( n = 17) and nonresponders ( n = 15) to altitude training on the basis of the change in sea-level 5,000-m run time determined before and after 28 days of living at moderate altitude and training at either low or moderate altitude. In addition, 22 elite runners were examined prospectively to confirm the significance of these factors in a separate population. In the retrospective analysis, responders displayed a significantly larger increase in erythropoietin (Epo) concentration after 30 h at altitude compared with nonresponders. After 14 days at altitude, Epo was still elevated in responders but was not significantly different from sea-level values in nonresponders. The Epo response led to a significant increase in total red cell volume andV˙o 2 max in responders; in contrast, nonresponders did not show a difference in total red cell volume or V˙o 2 maxafter altitude training. Nonresponders demonstrated a significant slowing of interval-training velocity at altitude and thus achieved a smaller O2 consumption during those intervals, compared with responders. The acute increases in Epo and V˙o 2 maxwere significantly higher in the prospective cohort of responders, compared with nonresponders, to altitude training. In conclusion, after a 28-day altitude training camp, a significant improvement in 5,000-m run performance is, in part, dependent on 1) living at a high enough altitude to achieve a large acute increase in Epo, sufficient to increase the total red cell volume andV˙o 2 max, and 2) training at a low enough altitude to maintain interval training velocity and O2 flux near sea-level values.

Acute Blood Pressure Response to High- and Moderate-Speed Resistance Exercise in Older Adults With Hypertension

2021 ◽  
pp. 1-8
Author(s):  
Carlos Leonardo Figueiredo Machado ◽  
Régis Radaelli ◽  
Clarissa Muller Brusco ◽  
Eduardo Lusa Cadore ◽  
Eurico N. Wilhelm ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Older Adults ◽  
Resistance Exercise ◽  
Blood Pressure Response ◽  
Individual Response ◽  
Older Individuals ◽  
Repetition Maximum ◽  
Control Protocol ◽  
The Individual ◽  
And Control

An increase in blood pressure (BP) occurs during resistance exercise; attention to this response may be necessary in older individuals with hypertension. We compared the BP responses following high- (HSRE) and moderate-speed resistance exercise (MSRE) (4 × 8 repetitions at 60% one-repetition maximum) and control protocol in 15 older adults with hypertension. HSRE and MSRE increased systolic BP (SBP) by the end of each set compared with preexercise and control protocol. Immediately after the fourth set, a higher SBP was observed in MSRE than HSRE (147 ± 14 vs. 141 ± 12 mmHg; p = .01). Taking an exploratory analysis of the individual response, we observed that MSRE resulted in greater mean changes and number of SBP exposures to values ≥150 mmHg (22-fold) than HSRE (10-fold). Diastolic BP increased (p < .05) with exercise, but only MSRE increased compared with the control condition (p < .05). HSRE may be an alternative for individuals in which SBP peak should be avoided.

scholarly journals Immune Homeostasis: New Role of Micro- and Macroelements, Healthy Microbiota

2020 ◽  
Vol 6 (10) ◽  
pp. 206-233
Author(s):  
S. Bulgakova ◽  
N. Romanchuk
Keyword(s):  
Immune System ◽  
Gut Microbiota ◽  
Immune Responses ◽  
Immunological Tolerance ◽  
Immune Homeostasis ◽  
Individual Response ◽  
Protective Mechanisms ◽  
Medical Program ◽  
Genetic And Environmental Factors ◽  
The Individual

The availability of innovative technologies, such as next-generation sequencing and correlated bioinformatics tools, allows deeper investigation of the cross-network relationships between the microbiota and human immune responses. Immune homeostasis is the balance between immunological tolerance and inflammatory immune responses — a key feature in the outcome of health or disease. A healthy microbiota is the qualitative and quantitative ratio of diverse microbes of individual organs and systems, maintaining the biochemical, metabolic and immune equilibrium of the macroorganism necessary to preserve human health. The studies of P. I. Romanchuk found that the microbiota is a key element potentially capable of influencing antigen functions to induce a protective immune response and the ability of the immune system to adequately respond to antigenic stimulation (vaccine efficacy) by acting as an immunological modulator as well as a natural vaccine adjuvant. The mechanisms underlying the crosstalk between the gut microbiota and the immune system play a crucial role, especially at an early age (early gut microbiota forms immunological functions). New interactions, along with other genetic and environmental factors, lead to a certain composition and richness of the microbiota, which can diversify the individual response to vaccinations. Variations in microbial communities may explain the geographical effectiveness of vaccination. Modern technologies for quantifying the specific and functional characteristics of the microbiota of the gastrointestinal tract, along with fundamental and new concepts in the field of immunology, have revealed numerous ways in which the interaction of the host and microbiota proceeds favorably, neutrally or unfavorably. The gut microbiota has a strong influence on the shape and quality of the immune system, respectively, the immune system determines the composition and localization of the microbiota. Thus, a healthy microbiota directly modulates intestinal and systemic immune homeostasis. The new managed healthy biomicrobiota and personalized functional and balanced nutrition of the “brain and microbiota” is a patient's long-term medical program that allows the combined use of nutritional epigenetics and pharmacepigenetics, and most importantly, an increase in the protective mechanisms of immunity.

scholarly journals Structure and mechanics of aegagropilae fiber network

2017 ◽  
Vol 114 (18) ◽  
pp. 4607-4612 ◽  
Author(s):  
Gautier Verhille ◽  
Sébastien Moulinet ◽  
Nicolas Vandenberghe ◽  
Mokhtar Adda-Bedia ◽  
Patrice Le Gal
Keyword(s):  
Mechanical Response ◽  
Posidonia Oceanica ◽  
Biological Tissues ◽  
Individual Response ◽  
Fiber Network ◽  
Friction Forces ◽  
Fiber Clustering ◽  
Wide Range ◽  
Natural Aggregates ◽  
The Individual

Fiber networks encompass a wide range of natural and manmade materials. The threads or filaments from which they are formed span a wide range of length scales: from nanometers, as in biological tissues and bundles of carbon nanotubes, to millimeters, as in paper and insulation materials. The mechanical and thermal behavior of these complex structures depends on both the individual response of the constituent fibers and the density and degree of entanglement of the network. A question of paramount importance is how to control the formation of a given fiber network to optimize a desired function. The study of fiber clustering of natural flocs could be useful for improving fabrication processes, such as in the paper and textile industries. Here, we use the example of aegagropilae that are the remains of a seagrass (Posidonia oceanica) found on Mediterranean beaches. First, we characterize different aspects of their structure and mechanical response, and second, we draw conclusions on their formation process. We show that these natural aggregates are formed in open sea by random aggregation and compaction of fibers held together by friction forces. Although formed in a natural environment, thus under relatively unconstrained conditions, the geometrical and mechanical properties of the resulting fiber aggregates are quite robust. This study opens perspectives for manufacturing complex fiber network materials.

scholarly journals Increased Hypothalamic Signal Transducer and Activator of Transcription 3 Phosphorylation after Hindbrain Leptin Injection

Endocrinology ◽  
2010 ◽  
Vol 151 (4) ◽  
pp. 1509-1519 ◽  
Author(s):  
Marieke Ruiter ◽  
Patricia Duffy ◽  
Steven Simasko ◽  
Robert C. Ritter
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Fourth Ventricle ◽  
Leptin Receptor ◽  
Janus Kinase ◽  
Signal Transducer ◽  
Solitary Tract ◽  
Stat3 Signaling ◽  
Stat3 Phosphorylation ◽  
Transcription 3

Reduction of food intake and body weight by leptin is attributed largely to its action in the hypothalamus. However, the signaling splice variant of the leptin receptor, LRb, also is expressed in the hindbrain, and leptin injections into the fourth cerebral ventricle or dorsal vagal complex are associated with reductions of feeding and body weight comparable to those induced by forebrain leptin administration. Although these observations suggest direct hindbrain action of leptin on feeding and body weight, the possibility that hindbrain leptin administration also activates the Janus kinase/signal transducer and activator of transcription 3 (STAT3) signaling in the hypothalamus has not been investigated. Confirming earlier work, we found that leptin produced comparable reductions of feeding and body weight when injected into the lateral ventricle or the fourth ventricle. We also found that lateral and fourth ventricle leptin injections produced comparable increases of STAT3 phosphorylation in both the hindbrain and the hypothalamus. Moreover, injection of 50 ng of leptin directly into the nucleus of the solitary tract also increased STAT3 phosphorylation in the hypothalamic arcuate and ventromedial nuclei. Increased hypothalamic STAT3 phosphorylation was not due to elevation of blood leptin concentrations and the pattern of STAT3 phosphorylation did not overlap distribution of the retrograde tracer, fluorogold, injected via the same cannula. Our observations indicate that even small leptin doses administered to the hindbrain can trigger leptin-related signaling in the forebrain, and raise the possibility that STAT3 phosphorylation in the hypothalamus may contribute to behavioral and metabolic changes observed after hindbrain leptin injections.

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