title: Gastric emptying and Ca(2+) and K(+) channels of circular smooth muscle cells in diet-induced obese prone and resistant rats.
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 (Ca(2+) ) and potassium (K(+) ) channels of antral circular smooth muscle cells (SMCs).
  
  
  METHODS
  Whole-cell patch-clamp technique was used to measure Ca(2+) 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 Ca(2+) 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 (IKto ) was more depolarized (∼4 mV) in DIO-P 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.
  
  
  CONCLUSIONS
  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.
authors: Veterans Research and Education Foundation, VA Medical Center, Oklahoma, Oklahoma, USA.
authors: Shiying
authors: S
authors: Li
authors: Roland
authors: R
authors: Maude-Griffin
authors: Andrew J
authors: AJ
authors: Pullan
authors: Jiande D Z
authors: JD
authors: Chen
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D004032:Diet; D059305:Diet, High-Fat; D005746:Gastric Emptying / Q000502:physiology*; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology; D009765:Obesity / Q000139:chemically induced / Q000503:physiopathology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019789:Tetraethylammonium / Q000494:pharmacology; D015430:Weight Gain
chemical_list: D015220:Calcium Channels; D015221:Potassium Channels; D019789:Tetraethylammonium; D015761:4-Aminopyridine; D009543:Nifedipine