Leçons de physiologie expérimentale appliquée à la médecine, faites au Collège de France,

Bernard, Claude

doi:10.5962/bhl.title.1818

Cited by 133 publications

(82 citation statements)

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“…Remarkably, he also showed in rabbits that "piqûre" (pricking) of the floor of the fourth ventricle of the brain resulted in glucosuria (1) and concluded that the CNS plays an essential role in the control of peripheral blood glucose levels. More recently, insulin signaling in neuronal cells has been shown to regulate life span, growth, reproduction, and energy homeostasis in primitive organisms such as Caenorhabditis elegans and Drosophila melanogaster (2,3).…”

Section: History and Backgroundmentioning

confidence: 99%

Central insulin action in energy and glucose homeostasis

Plum

Belgardt²,

Brüning³

2006

Journal of Clinical Investigation

368

271

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Insulin has pleiotropic biological effects in virtually all tissues. However, the relevance of insulin signaling in peripheral tissues has been studied far more extensively than its role in the brain. An evolving body of evidence indicates that in the brain, insulin is involved in multiple regulatory mechanisms including neuronal survival, learning, and memory, as well as in regulation of energy homeostasis and reproductive endocrinology. Here we review insulin's role as a central homeostatic signal with regard to energy and glucose homeostasis and discuss the mechanisms by which insulin communicates information about the body's energy status to the brain. Particular emphasis is placed on the controversial current debate about the similarities and differences between hypothalamic insulin and leptin signaling at the molecular level. History and backgroundMore than 150 years ago, the French physiologist Claude Bernard identified the liver as a reservoir for glucose. Remarkably, he also showed in rabbits that "piqûre" (pricking) of the floor of the fourth ventricle of the brain resulted in glucosuria (1) and concluded that the CNS plays an essential role in the control of peripheral blood glucose levels. More recently, insulin signaling in neuronal cells has been shown to regulate life span, growth, reproduction, and energy homeostasis in primitive organisms such as Caenorhabditis elegans and Drosophila melanogaster (2, 3). The insulin/IGF-1 signal transduction pathway shows similar characteristics in C. elegans, D. melanogaster, rodents, and humans, pointing to an evolutionarily conserved mechanism (4). Signaling of the insulin/IGF-1 receptor homolog dauer formation-2 (DAF-2) via the class IA PI3K (AGE-1) pathway in C. elegans has been shown to control development, reproductive function, and longevity in response to environmental stimuli such as energy supply, a mechanism involving the forkhead-O transcription factor (FOXO) homolog 6). Likewise, the insulin receptor substrate (IRS) protein homolog CHICO in D. melanogaster regulates somatic growth, reproduction, and lipid metabolism (7).It has been shown that overexpression of D. melanogaster insulinlike peptides (dILPs) in the nervous system of fasted larvae suppresses the hunger-driven ingestion of food and that upregulation of D. melanogaster p70/S6 kinase (dS6K) activity in dILP neurosecretory cells leads to a diminished hunger response in fasted larvae (8). Furthermore, ablation of dILP neurons in the Drosophila brain was found to result in prolonged lifespan, reduced fertility, increased fasting glucose levels, increased storage of lipids and carbohydrates, and reduced tolerance to heat and cold (2, 9), clearly assigning neurosecretory cells a pivotal importance in the regulation of lifespan and fuel metabolism in D. melanogaster.The finding that insulin, like the adipocyte-derived hormone leptin, affects both neuropeptide expression in the hypothalamus and food intake has recently led to the appreciation of the brain as an insulin target tissue with regard t...

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Section: History and Backgroundmentioning

confidence: 99%

Central insulin action in energy and glucose homeostasis

Plum

Belgardt²,

Brüning³

2006

Journal of Clinical Investigation

368

271

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“…For over 50 years the major influence on the study of food intake arose from the tradition of homeostasis and the concepts of Claude Bernard (49) . This tradition was expressed through early theories of motivation (50) .…”

Section: Homeostasis and Hedonics: Combined Influence On Appetitementioning

confidence: 99%

The influence of physical activity on appetite control: an experimental system to understand the relationship between exercise-induced energy expenditure and energy intake

et al. 2011

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Investigations of the impact of physical activity on appetite control have the potential to throw light on the understanding of energy balance and therefore, upon body weight regulation and the development of obesity. Given the complexity of the landscape influencing weight regulation, research strategies should reflect this complexity. We have developed a research approach based on the concept of the psychobiological system (multi-level measurement and analysis) and an experimental platform that respects the operations of an adaptive regulating biological system. It is important that both sides of the energy balance equation (activity and diet) receive similar detailed levels of analysis. The experimental platform uses realistic and fully supervised levels of physical activity, medium-term (not acute) interventions, measurement of body composition, energy metabolism (indirect calorimetry), satiety physiology (gut peptides), homeostatic and hedonic processes of appetite control, non-exercise activity, obese adult participants and both genders. This research approach has shown that the impact of physical activity on appetite control is characterised by large individual differences. Changes in body composition, waist circumference and health benefits are more meaningful than changes in weight. Further, we are realising that the acute effects do not predict what will happen in the longer term. The psychobiological systems approach offers a strategy for simultaneously investigating biological and behavioural processes relevant to understanding obese people and how obesity can be managed. This experimental platform provides opportunities for industry to examine the impact of foods under scientifically controlled conditions relevant to the real world.

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“…Cannon's theory, however, was superseded when physiological data made clear the dominance of hypothalamic neural genesis of thirst. Anteceding Cannon, Claude Bernard (6) showed in animals with esophageal (horse) and gastric (dog) fistulae that drinking would continue to the point of exhaustion, despite the wetness of the oral mucosa. Nevertheless, a dry mouth is subjectively experienced as thirst (i.e., does lead to drinking) and must be controlled in the course of an experiment directed at the brain mechanisms of osmoregulation, as is reported here.…”

mentioning

confidence: 99%

Correlation of regional cerebral blood flow and change of plasma sodium concentration during genesis and satiation of thirst

Denton

Shade

Zamarippa

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

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Positron emission tomography studies were conducted during genesis of moderate thirst by rapid i.v. infusion of hypertonic saline (0.51 M) and after satiation of thirst by drinking water. The correlation of regional cerebral blood f low with the change in the plasma Na concentration showed a significant group of cerebral activations in the anterior cingulate region and also a site in the middle temporal gyrus and in the periaqueductal gray. Strongest deactivations occurred in the parahippocampal and frontal gyri. The data are consistent with an important role of the anterior cingulate in the genesis of thirst.

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Leçons de physiologie expérimentale appliquée à la médecine, faites au Collège de France,

Cited by 133 publications

References 0 publications

Central insulin action in energy and glucose homeostasis

Central insulin action in energy and glucose homeostasis

The influence of physical activity on appetite control: an experimental system to understand the relationship between exercise-induced energy expenditure and energy intake

Correlation of regional cerebral blood flow and change of plasma sodium concentration during genesis and satiation of thirst

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