title: Cholecystokinin-8 increases Fos-like immunoreactivity in the brainstem and myenteric neurons of rats through CCK1 receptors.
abstract: To examine the role of cholecystokinin1 receptor (CCK1) in the activation of brainstem and myenteric neurons by CCK, we compared the ability of exogenous CCK-8 to induce Fos-like immunoreactivity (Fos-LI) in these neurons in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, lacking CCK1 receptors, and Long-Evans Tokushima Otsuka (LETO) controls. Five groups (n=4 rats per group) of OLETF rats, and five LETO control groups, were injected intraperitoneally (IP) with 5, 10, 20, and 40 microg/kg CCK-8 or saline. Forty-micrometer brainstem sections containing the area postrema, nucleus of the solitary tract, and the dorsal motor nucleus of the vagus, and myenteric neurons of the duodenum, jejunum, and ileum underwent a diaminobenzidine reaction enhanced with nickel to reveal Fos-LI. CCK-8 did not increase Fos-LI in any of the tested neurons in the OLETF rats. CCK-8 increased Fos-LI in the brainstem of the LETO rats in a dose dependent manner. In the LETO rats only 40 microg/kg CCK-8 increased Fos-LI in the myenteric plexus of the jejunum. This study demonstrates that CCK-8 activates the brainstem and myenteric neurons through the CCK1 receptor.
authors.affiliation: Gastroenterology Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Tuskegee University, Tuskegee, AL 36088, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Gulley
authors.forename: Sanjay K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Moran
authors.forename: Ayman I
authors.initials: AI
authors.lastname: Sayegh
mesh_terms: D000818:Animals; D031608:Area Postrema / Q000187:drug effects / Q000378:metabolism; D001933:Brain Stem / Q000187:drug effects* / Q000378:metabolism; D002766:Cholecystokinin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004386:Duodenum / Q000187:drug effects / Q000378:metabolism; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D007150:Immunohistochemistry; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009154:Mutation; D009197:Myenteric Plexus / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D051381:Rats; D020334:Rats, Inbred OLETF; D020318:Rats, Long-Evans; D043886:Receptor, Cholecystokinin A / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D017552:Solitary Nucleus / Q000187:drug effects / Q000378:metabolism; D014630:Vagus Nerve / Q000187:drug effects / Q000378:metabolism
chemical_list: D010446:Peptide Fragments; D016760:Proto-Oncogene Proteins c-fos; D043886:Receptor, Cholecystokinin A; C410885:cholecystokinin 8; D002766:Cholecystokinin