title: Two types of leptin-responsive gastric vagal afferent terminals: an in vitro single-unit study in rats.
abstract: In vitro gastric vagal afferents' (GVAs) unit activities were recorded from the ventral GVA nerve strands in rats. The responsiveness of 16 GVA terminals to close intra-arterial injection of vehicle (0.1 ml), leptin (350 pmol), and cholecystokinin (CCK)-8 (10 pmol) was analyzed to generate a spike count-versus-time histogram. Data of 5-min spike counts before and after each treatment were normalized by dividing the latter by the former. A quotient (Q) > 1 indicates an excitatory effect, Q < 1 indicates an inhibitory effect, and Q close to 1 indicates no effect. Two types of GVA terminals were identified. Type 1 (n = 8) responded to leptin with Q > 1; CCK-8 pretreatment did not consistently alter leptin sensitivity. In contrast, Type 2 (n = 8) responded to leptin with Q < 1 or close to 1, and CCK-8 pretreatment increased the leptin sensitivity so that the terminals responded to subsequent leptin with Q > 1. These data suggest that Type 1 and Type 2 GVA terminals may provide afferent neural signals, which, in turn, will be involved in body weight and food intake control systems, respectively.
authors.affiliation: Center for Ulcer Research and Education/Digestive Diseases Research Center, Los Angeles, California, USA.
authors.forename: Y H
authors.initials: YH
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Taché
authors.forename: A B
authors.initials: AB
authors.lastname: Sheibel
authors.forename: V L
authors.initials: VL
authors.lastname: Go
authors.forename: J Y
authors.initials: JY
authors.lastname: Wei
mesh_terms: D000818:Animals; D007269:Injections, Intra-Arterial; D020738:Leptin; D008297:Male; D008465:Mechanoreceptors / Q000187:drug effects; D009411:Nerve Endings / Q000187:drug effects*; D009475:Neurons, Afferent / Q000187:drug effects*; D014677:Pharmaceutical Vehicles; D011506:Proteins / Q000494:pharmacology*; D051381:Rats; D012844:Sincalide / Q000494:pharmacology; D013270:Stomach / Q000294:innervation*; D014630:Vagus Nerve / Q000166:cytology / Q000187:drug effects*
chemical_list: D020738:Leptin; D014677:Pharmaceutical Vehicles; D011506:Proteins; D012844:Sincalide