dynorphins and thioperamide

Whether or not neuropeptide Y (NPY)-induced feeding in rats is influenced by the histaminergic system in the brain was investigated by intracerebroventricular (i.c.v.) administration of a selective histamine H3 receptor antagonist prior to i.c.v. administration of NPY. NPY (10 microg/10 microl) strongly induced feeding in sated rats during the light phase of the day. Dynorphin A1-17 (10 microg/10 microl), a kappa-opioid agonist, and rat pancreatic polypeptide (rPP, 30 microg/10 microl) also stimulated ingestive behavior in sated rats, but food intake in both cases was less than that induced by NPY. Thioperamide maleate, a specific histamine H3 receptor antagonist (408.5 microg/10 microl) reduced the feeding response to NPY by 52% (P < 0.0001), but not to dynorphin A1-17 and rPP. Thioperamide at i.c.v. doses of 40.8-408.5 microg/10 microl had no effect on food intake in sated rats. These results suggest that the thioperamide may have a specific effect on NPY receptor-mediated neuronal systems related to feeding.

Topics: Animals; Dynorphins; Eating; Histamine Antagonists; Injections, Intraventricular; Male; Neuropeptide Y; Pancreatic Polypeptide; Peptide YY; Piperidines; Rats; Rats, Wistar; Receptors, Histamine H3; Receptors, Opioid, kappa