Project: Research project

Project Details


The overriding aim of this proposal is to identify meal-related stimuli
arising from the stomach, small intestine and liver that elicit vagal
afferent activity in the rat, and to determine how gastrointestinal events
associated with food intake may be integrated at the level of the
peripheral afferent vagus. The underlying basis of the experiments
addressing these aims is the view that mechanical and chemical stimuli in
the stomach, small intestine and liver provoked by food intake provide
information critical to the control of feeding. The vagus nerve is a
major neuroanatomical pathway linking gastrointestinal and central nervous
system sites involved in food intake control. Using in vivo
electrophysiological techniques, we propose to identify and characterize
vagal afferent fibers with gastric, small intestinal and hepatic receptive
fields. We will begin by classifying these fibers according to their
responsiveness to distension and chemical stimulation. This
classification will provide the basis for subsequent experiments designed
to examine the mechanisms giving rise to these signals. For distension
sensitive fibers, we will examine the relationship of this sensitivity to
changes in local gastrointestinal pressure and muscle tension. Using
pharmacological and neural disconnection techniques, we will also examine
the dependence of these signals on extrinsic sympathetic and
parasympathetic innervation. For chemosensitive fibers, we will
characterize the nature of their sensitivity, examining their responses to
pH, osmolarity, and elemental macronutrient stimuli. We will perform
experiments evaluating the extent to which these vagal afferents integrate
stimulation from multiple gastrointestinal and hepatic sites. Following
identification of these types of integration, we will examine the neural,
neurotransmitter and neuroendocrine mediation of this vagal afferent
integration. Together, these experiments will significantly advance our
understanding of vagal afferent signals elicited by meal-related
gastrointestinal events that may play a role in the control of food
intake, in gastrointestinal physiology and in body weight regulation.
Effective start/end date8/20/947/31/95


  • National Institute of Diabetes and Digestive and Kidney Diseases


  • Endocrine and Autonomic Systems
  • Sensory Systems
  • Gastroenterology
  • Nutrition and Dietetics
  • Physiology

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