title: Gut vagal afferents are necessary for the eating-suppressive effect of intraperitoneally administered ginsenoside Rb1 in rats.
abstract: Ginsenoside Rb1 (Rb1) reduces food intake in both lean and high-fat diet induced-obese rats; however, the sites and/or mediation of the eating-suppressive effect of Rb1 have not previously been identified. We hypothesized that intraperitoneally (ip) administered Rb1 exerts its anorectic action by enhancing sensitivity to satiation signals, such as cholecystokinin (CCK), and/or that it acts through vagal afferent nerves that relay the satiating signaling to the hindbrain. To test these hypotheses, we gave ip bolus doses of Rb1 (2.5-10.0mg/kg) and CCK-8 (0.125-4.0μg/kg) alone or in combination and assessed food intake in rats. Low doses of Rb1 (2.5mg/kg) or CCK-8 (0.125μg/kg) alone had no effect on food intake whereas higher doses did. When these subthreshold doses of Rb1 and CCK-8 were co-administered, the combination significantly reduced food intake relative to saline controls, and this effect was attenuated by lorglumide, a selective CCK1-receptor antagonist. Interestingly, lorglumide blocked food intake induced by an effective dose of CCK-8 alone, but not by Rb1 alone, suggesting that Rb1's anorectic effect is independent of the CCK1 receptor. To determine whether peripherally administered Rb1 suppresses feeding via abdominal vagal nerves, we evaluated the effect of ip Rb1 injection in subdiaphragmatic vagal deafferentation (SDA) and control rats. Rb1's effect on food intake was significantly attenuated in SDA rats, compared with that in SHAM controls. These data indicate that the vagal afferent system is the major pathway conveying peripherally administered Rb1's satiation signal.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA.
authors.forename: Ling
authors.initials: L
authors.lastname: Shen
authors.affiliation: Department of Internal Medicine, Saint Louis University School of Medicine, St. Louis, MO 63104, USA.
authors.forename: David Q-H
authors.initials: DQ
authors.lastname: Wang
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA.
authors.forename: Chunmin C
authors.initials: CC
authors.lastname: Lo
authors.affiliation: Institute of Food, Nutrition and Health, Swiss Federal Institute of Technology Zurich, Schwerzenbach 8603, Switzerland.
authors.forename: Myrtha
authors.initials: M
authors.lastname: Arnold
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Tso
authors.affiliation: Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Woods
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45237, USA. Electronic address: lium@uc.edu.
authors.forename: Min
authors.initials: M
authors.lastname: Liu
mesh_terms: D000818:Animals; D001067:Appetite Depressants / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D036145:Ginsenosides / Q000008:administration & dosage*; D005947:Glucose; D006727:Hormone Antagonists / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D008297:Male; D009475:Neurons, Afferent / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D011377:Proglumide / Q000031:analogs & derivatives / Q000494:pharmacology; D020318:Rats, Long-Evans; D043886:Receptor, Cholecystokinin A / Q000037:antagonists & inhibitors / Q000378:metabolism; D012527:Satiation / Q000187:drug effects / Q000502:physiology; D012844:Sincalide / Q000008:administration & dosage*; D014630:Vagus Nerve / Q000166:cytology / Q000187:drug effects* / Q000502:physiology
chemical_list: D001067:Appetite Depressants; D036145:Ginsenosides; D006727:Hormone Antagonists; D043886:Receptor, Cholecystokinin A; C442759:ginsenoside Rb1; D011377:Proglumide; D005947:Glucose; C048181:lorglumide; D012844:Sincalide
keywords: CCK; Food intake; Ginsenoside; Vagus nerve