title: Chronic treatment with epigallocatechin gallate reduces motor hyperactivity and affects in vitro tested intestinal motility of spontaneously hypertensive rats.
abstract: BACKGROUND
  Green tea catechins seem to contribute toward reducing body weight and fat.
  
  
  OBJECTIVE
  We aimed to investigate whether chronic administration of (-)-epigallocatechin-3-gallate (EGCG), the most abundant catechin of green tea, reduces weight gain in spontaneously hypertensive rats (SHR), an animal model of metabolic syndrome, by increasing motor activity and/or by altering gastrointestinal motility.
  
  
  METHODS
  Nine-week-old SHR were randomly assigned to two groups and treated by gavage for 3 weeks with vehicle dimethyl sulfoxide or EGCG (200 mg/kg/day). Age-matched Wistar-Kyoto (WKY) control rats were treated with vehicle alone. The effect of chronic administration of EGCG was evaluated on open-field motor activity and on ex vivo colonic and duodenal motility. Moreover, in vitro acute effect of 20-min incubation with EGCG (100 µM) or vehicle was evaluated in colonic and duodenal specimens from untreated WKY rats and SHR.
  
  
  RESULTS
  Vehicle-treated SHR were normoglycemic and hyperinsulinemic, and showed a reduction of plasma adiponectin when compared to vehicle-treated WKY rats. In addition, consistent with fasting glucose and insulin values, vehicle-treated SHR were more insulin resistant than age-matched vehicle-treated WKY rats. Chronic treatment for 3 weeks with EGCG improved insulin sensitivity, raised plasma adiponectin levels, and reduced food intake and weight gain in SHR. Vehicle-treated SHR showed increased open-field motor activity (both crossings and rearings) when tested after each week of treatment. The overall hyperactivity of vehicle-treated SHR was significantly reduced to the levels of vehicle-treated WKY rats after 2 and 3 weeks of EGCG treatment. Colonic and duodenal preparations obtained from SHR chronically treated in vivo with EGCG showed reduced responses to carbachol (0.05-5 µM) and increased inhibitory response to electrical field stimulation (EFS, 1-10 Hz, 13 V, 1 msec, 10-sec train duration), respectively. In vitro acute EGCG incubation (100 µM, 20 min) of colonic and duodenum strips obtained from untreated SHR and WKY rats showed a reduced contractile colonic response to a fixed dose of carbachol (1.5 µM) only in SHR with respect to its own vehicle, whereas the inhibitory duodenal response to a fixed EFS frequency (5 Hz) was significantly reduced in both WKY rats and SHR groups with respect to their own vehicle.
  
  
  CONCLUSIONS
  These data suggest that EGCG affects body weight gain in rats and this effect seems to be due to the altered intestinal motility and not to increased motor activity.
authors.affiliation: Department of Biomedical Sciences and Human Oncology, University of Bari 'Aldo Moro', Bari, Italy.
authors.forename: Maria Assunta
authors.initials: MA
authors.lastname: Potenza
authors.affiliation: Department of Biomedical Sciences and Human Oncology, University of Bari 'Aldo Moro', Bari, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Montagnani
authors.affiliation: Department of Biomedical Sciences and Human Oncology, University of Bari 'Aldo Moro', Bari, Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Nacci
authors.affiliation: Department of Biomedical Sciences and Human Oncology, University of Bari 'Aldo Moro', Bari, Italy; mariaantonietta.desalvia@uniba.it.
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: De Salvia
keywords: colon; duodenum; green tea; weight gain