Gastric emptying and Ca2+ and K+ channels of circular smooth muscle cells in diet-induced obese prone and resistant rats

Shiying Li, Roland Maude-Griffin, Andrew J. Pullan, Jiande D.Z. Chen

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: Accelerated gastric emptying that precipitates hunger and frequent eating could be a potential factor in the development of obesity. The aim of this study was to study gastric emptying in diet-induced obese-prone (DIO-P) and DIO-resistant (DIO-R) rats and explore possible differences in electrical properties of calcium (Ca2+) and potassium (K+) channels of antral circular smooth muscle cells (SMCs). Design and Methods: Whole-cell patch-clamp technique was used to measure Ca2+ and K + currents in single SMCs. Gastric emptying was evaluated 90 min after the ingestion of a solid meal. Results: Solid gastric emptying in the DIO-P rats was significantly faster compared with that in the DIO-R rats. The peak amplitude of L-type Ca2+ current (IBa,L) at 10 mV in DIO-P rats was greater than that in DIO-R rats without alternation of the current-voltage curve and voltage-dependent activation and inactivation. The half-maximal inactivation voltage of transient outward K+ current (I Kto) was more depolarized (∼4 mV) in DIOP rats compared with that in DIO-R rats. No difference was found in the current density or recovery kinetics of IKto between two groups. The current density of delayed rectifier K+ current (IKdr), which was sensitive to tetraethylammonium chloride but not 4-aminopyridine, was lower in DIO-P rats than that in DIO-R rats. Conclusion: The accelerated gastric emptying in DIO-P rats might be attributed to a higher density of IBa,L, depolarizing shift of inactivation curve of IKto and lower density of IKdr observed in the antral SMCs of DIO-P rats.

Original languageEnglish (US)
Pages (from-to)326-335
Number of pages10
JournalObesity
Volume21
Issue number2
DOIs
StatePublished - Feb 2013

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Nutrition and Dietetics

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