Gastrin releasing peptide-29 requires vagal and splanchnic neurons to evoke satiation and satiety.
We have shown that gastrin-releasing peptide-29 (GRP-29), the large molecular form of GRP in rats, reduces meal size (MS, intake of 10% sucrose solution) and prolongs the intermeal interval (IMI). In these studies, we first investigated possible pathways for these responses in rats undergoing total subdiaphragmatic vagotomy (VGX, removal of vagal afferent and efferent innervation of the gut), celiaco-mesenteric ganglionectomy (CMGX, removal of splanchnic afferent and efferent innervation of the gut) and combined VGX and CMGX. Second, we examined if the duodenum communicates the feeding signals (MS and IMI) of GRP-29 (0, 0.3, 1.0, 2.1, 4.1, 10.3 and 17.2 nmol/kg) with the feeding control areas of the hindbrain by performing duodenal myotomy (MYO), a procedure that severs some layers of the duodenal wall including the vagal, splanchnic and enteric neurons. We found that GRP-29 (2.1, 4.1, 10.3, 17.2 nmol/kg) reduced the size of the first meal (10% sucrose) and (1, 4.1, 10.3 nmol/kg) prolongs the first IMI but did not affect the subsequent meals or IMIs. In addition, CMGX and combined VGX/CMGX attenuated reduction of MS by GRP-29 and all surgeries attenuated the prolongation of the IMI. Therefore, reduction of MS and prolongation of IMI by GRP-29 require vagal and splanchnic nerves, and the duodenum is the major conduit that communicates prolongation of IMI by GRP-29 with the brain.
Gastroenterology Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Tuskegee University, Tuskegee, AL 36088, United States.
Susan A
SA
Wright
Martha C
MC
Washington
Carlos
C
Garcia
Ayman I
AI
Sayegh
D000818:Animals; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000294:innervation / Q000378:metabolism / Q000601:surgery; D004435:Eating / Q000187:drug effects; D017615:Enteric Nervous System / Q000378:metabolism; D005728:Ganglia, Sympathetic / Q000601:surgery; D015171:Ganglionectomy; D019886:Gastrin-Releasing Peptide / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012527:Satiation / Q000187:drug effects / Q000502:physiology*; D013153:Splanchnic Nerves / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014628:Vagotomy / Q000379:methods; D014630:Vagus Nerve / Q000502:physiology / Q000601:surgery
D019886:Gastrin-Releasing Peptide