title: Influence of fasting, insulin and glucose on ghrelin in the dorsal vagal complex in rats.
abstract: The dorsal vagal complex (DVC) is an important site in which ghrelin plays an orexigenic role. However, the relationship between ghrelin expression in DVC and the energy status of the organism is unclear, as well as the role of the vagus nerve in this process. In this study, ghrelin expression in DVC neurons of rats was detected, then levels of ghrelin expression were observed under the conditions of regular diet, fasting, high blood glucose, low blood glucose, and following subdiaphragmatic vagotomy and vagus nerve electrostimulation. The results showed the following: 1) there was positive staining of ghrelin neurons in DVC; 2) ghrelin protein and mRNA levels in DVC increased under fasting condition; 3) Hyperglycemia, induced by glucose production, decreased DVC ghrelin levels and levels did not increase under hypoglycemia induced by insulin injection; 4) the dorsal trunk of the subdiaphragmatic vagus transmits a stimulatory signal to increase DVC ghrelin levels, whereas the ventral trunk transmits inhibitory information; and 5) DVC ghrelin levels decreased with 20 Hz stimulation on the ventral or dorsal trunk of subdiaphragmatic vagus nerves but increased with 1 Hz stimulation on the dorsal trunk. These results indicate that endogenous ghrelin is synthesized in DVC neurons. Conditions such as fasting, hyperglycemia, and hypoglycemia result in changes in DVC ghrelin levels in which the dorsal and ventral trunks of subdiaphragmatic vagus play different modulation roles.
authors.affiliation: Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing 100191, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Bin
authors.initials: B
authors.lastname: Qiu
authors.forename: Lin
authors.initials: L
authors.lastname: Yuan
authors.forename: Lili
authors.initials: L
authors.lastname: Zheng
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Shigong
authors.initials: S
authors.lastname: Zhu
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D015153:Blotting, Western; D004558:Electric Stimulation; D005215:Fasting / Q000097:blood* / Q000502:physiology; D054439:Ghrelin / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D007328:Insulin / Q000097:blood*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D017552:Solitary Nucleus / Q000502:physiology; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*
chemical_list: D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D012333:RNA, Messenger