1987 — 1988 |
Kaplan, Joel Martin |
F32Activity Code Description: To provide postdoctoral research training to individuals to broaden their scientific background and extend their potential for research in specified health-related areas. |
Swallowing During Ongoing Ingestive Behavior @ University of Pennsylvania |
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1993 |
Kaplan, Joel Martin |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Oral, Gastric and Post-Gastric Contributions to Satiety @ University of Pennsylvania
There is universal agreement that only a fraction of the amount consumed during a meal is absorbed from the digestive system before the meal is terminated and that peripheral sensory systems, therefore, play a critical role in short-term satiety and in the control of meal size. However, considerable controversy surrounds the issue of the identity and location of the peripheral receptors from which satiety-relevant feedback originates. the debate is marked by the advocacy of single-organ models of satiety (e.g., "the stomach signals satiety") despite good evidence that receptors at several locations can provide complementary or redundant information about what has been ingested during the meal (volume, nutrient content, calories, etc.). As a result, almost no data speak to the integration of intake-inhibitory signals when feedback from oral, gastric and post-gastric sources are concurrently available. This is a serious omission for clinical approaches to feeding disorders and for neural investigations into substrates that modulate ingestive behavior as a function of physiological and metabolic variables. Experiments proposed will address these issues. The present experiments will provide a systematic analysis, in the rat, of the relative contributions of oral, gastric and post-gastric signals to terminating bouts of glucose ingestion initiated under controlled laboratory conditions. to determine the gastric versus post-gastric distribution of ingested glucose, measurement of the cumulative intake curve will be coordinated with what will be the first systematic measurements of gastric emptying during ingestion. It will thereby be possible to quantify the stimulatory effects of experimental manipulations (stimulus concentration, stimulus delivery rate, gastric infusions of glucose delivered at different rates in parallel with oral ingestion) designed to systematically bias the rate of glucose accumulation within the stomach relative to the rate at which glucose empties from the stomach. Their behavior impact will be evaluated in terms of (1) changes in meal size and meal duration, and (2) the amount of glucose within and beyond the stomach when meals are terminated. these experiments will lead to the identification of peripheral sources of satiety-relevant feedback and to an operational model for the integrative mechanisms that underlie short-term satiety under normal conditions when oral, gastric and postgastric receptors are stimulated concurrently.
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1 |
1994 — 1995 |
Kaplan, Joel Martin |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Oral, Gastric, and Postgastric Contributions to Satiety @ University of Pennsylvania
There is universal agreement that only a fraction of the amount consumed during a meal is absorbed from the digestive system before the meal is terminated and that peripheral sensory systems, therefore, play a critical role in short-term satiety and in the control of meal size. However, considerable controversy surrounds the issue of the identity and location of the peripheral receptors from which satiety-relevant feedback originates. the debate is marked by the advocacy of single-organ models of satiety (e.g., "the stomach signals satiety") despite good evidence that receptors at several locations can provide complementary or redundant information about what has been ingested during the meal (volume, nutrient content, calories, etc.). As a result, almost no data speak to the integration of intake-inhibitory signals when feedback from oral, gastric and post-gastric sources are concurrently available. This is a serious omission for clinical approaches to feeding disorders and for neural investigations into substrates that modulate ingestive behavior as a function of physiological and metabolic variables. Experiments proposed will address these issues. The present experiments will provide a systematic analysis, in the rat, of the relative contributions of oral, gastric and post-gastric signals to terminating bouts of glucose ingestion initiated under controlled laboratory conditions. to determine the gastric versus post-gastric distribution of ingested glucose, measurement of the cumulative intake curve will be coordinated with what will be the first systematic measurements of gastric emptying during ingestion. It will thereby be possible to quantify the stimulatory effects of experimental manipulations (stimulus concentration, stimulus delivery rate, gastric infusions of glucose delivered at different rates in parallel with oral ingestion) designed to systematically bias the rate of glucose accumulation within the stomach relative to the rate at which glucose empties from the stomach. Their behavior impact will be evaluated in terms of (1) changes in meal size and meal duration, and (2) the amount of glucose within and beyond the stomach when meals are terminated. these experiments will lead to the identification of peripheral sources of satiety-relevant feedback and to an operational model for the integrative mechanisms that underlie short-term satiety under normal conditions when oral, gastric and postgastric receptors are stimulated concurrently.
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1 |
1996 — 2005 |
Kaplan, Joel Martin |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Oral, Gastric and Postgastric Contributions to Satiety @ University of Pennsylvania
DESCRIPTION: (Adapted from the Investigator's Abstract) There is universal agreement that peripheral sensory systems play a critical role in the control of meal size and patterning. However, the origin of satiety-relevant feedback is a matter of some controversy. Researchers tend to focus on discrete sources (e.g., the stomach) or potentially relevant feedback and, as a result have not addressed the important issue of the integration of intake-inhibitory signals when feedback from disparate sources is concurrently available. This leaves important open issues for clinical approaches (both behavioral and pharmacological) to feeding disorders, and for neural investigation into substrates that modulate ingestive behavior as a function of physiological and metabolic variables. The proposed experiments will provide an analysis, in the rat, of the relative contributions of oral, gastric and post-gastric sources to the termination of individual test meals, and the size and spacing of meals ingested throughout the day. Analysis of gastric emptying is central to this research program insofar as emptying determines the proportion of the ingested load that contacts gastric and post-gastric receptors. Thus, several experiments address the distinction between mechanisms that control gastric emptying within versus between meals as functions of : quality, volume and concentration of nutrients ingested; oral versus gastric stimulus delivery; time of day/night; deprivation state; and CNS administration of pharmacological agents that affect peptide receptor systems of great contemporary interest for the control of ingestion (corticotropin releasing factor, melanocortin, and neuropeptide Y). For food intake studies, we develop and exploit specialized testing paradigms (intra-oral infusion, drop-size-controlled lickometry, automated meal pattern analysis with access-restriction capability). The ability to manipulate aspects of stimulus delivery facilitates the analysis of gastric emptying, and allows us to bring emptying and behavioral results/meal size, duration and spacing, into explicit register. To evaluate the relative emptying and behavioral results(meal size, duration and spacing) into explicit register, to evaluate the relative weightings of gastric and post-gastric sources to satiation and satiety, we will characterize ingestive responses to manipulation that systematically bias the accumulation of nutrients within and beyond the stomach (e.g., reversible pyloric occlusion, intra-gastric and intra-intestinal infusion, and pharmacological treatments).
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