Load-sensitive rat gastric vagal afferents encode volume but not gastric nutrients

Carole Mathis, Timothy H. Moran, Gary J. Schwartz

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Abstract

To assess nutrient sensitivity in a population of gastric load-sensitive vagal afferents, their neurophysiological activity was examined in anesthetized rats with inflated pyloric cuffs after gastric infusion of a range of volumes of nutrient and equiosmotic saline solutions. Responses to physiological saline loads (1, 2, 4, and 8 ml) were compared with responses elicited by the same volume range of carbohydrate (12.5% glucose), protein (12.5% peptone), and equiosmotic hypertonic (750 mosM) saline. The threshold load volume of physiological saline required to increase gastric vagal afferent activity was 1 ml. Thereafter, there was a dose-dependent relationship between increasing gastric volume and firing rate and between gastric volume and pressure. The dose-response relationships elicited by glucose, peptone, and equiosmotic hypertonic saline loads did not differ from those elicited by physiological saline loads. These data identify a population of gastric load-sensitive vagal afferents unresponsive to the chemical composition of gastric contents and are consistent with a role for vagal gastric volume signals but not gastric nutrient content in the negative feedback control of ingestion.

Original languageEnglish (US)
Pages (from-to)R280-R286
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume274
Issue number2 43-2
StatePublished - Feb 1 1998
Externally publishedYes

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Keywords

  • Brain-gut communication
  • Food intake
  • Vagus
  • Visceral afferents

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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