Role of the area postrema in the hypophagic effects of oleoylethanolamide. (August 2017)

• Record Type: Journal Article
• Authors: Romano, Adele; Gallelli, Cristina Anna; Koczwara, Justyna Barbara; Braegger, Fiona E.; Vitalone, Annabella; Falchi, Mario; Micioni Di Bonaventura, Maria Vittoria; Cifani, Carlo; Cassano, Tommaso; Lutz, Thomas A.; Gaetani, Silvana
• Is Part Of: Pharmacological research. Volume 122(2017:Aug.)
• Page Start: 20
• Page End: 34
• Publication Date: 2017-08
• Subjects: Oleoylethanolamide: (PubChem CID: 5283454); AP area postrema -- BBB blood brain barrier -- CCK cholecystokinin -- CNS central nervous system -- CTA conditioned taste aversion -- DAB 3, 3 diaminobenzidine-tetrahydrochloride -- DBH dopamine beta hydroxylase -- FAAH fatty acid amide hydrolase -- GLP-1 glucagon-like peptide-1 -- GPR119 "orphan" G-coupling receptor -- HDC histidine decarboxylase -- i.c.v. intracerebroventricular -- i.p. intraperitoneal -- NST nucleus of the solitary tract -- OD optical density -- OEA oleoylethanolamide -- OXY oxytocin -- PBS phosphate buffer saline -- PPAR-alpha peroxisome proliferator-activated-receptor-alpha -- PVN paraventricular nucleus -- PYY peptide YY -- sCT salmon calcitonin -- SDA subdiaphragmatic vagal deafferentation -- SolC nucleus of the solitary tract commisural part -- SolDM nucleus of the solitary tract dorsomedial part -- SolM nucleus of the solitary tract medial part -- SolVL nucleus of the solitary tract ventrolateral part -- SON supraoptic nucleus -- TMN tuberomammillary nucelus -- TRPV1 transient receptor potential cation channel vanilloid-1 -- VEH vehicle; Feeding behavior -- Area postrema -- Nucleus of the solitary tract -- Brainstem -- Hypothalamus -- Satiety; Pharmacology -- Periodicals; Pharmacology -- Periodicals; Research -- Periodicals; Médicaments -- Recherche -- Périodiques; Pharmacologie -- Périodiques; 615.105
• DOI: 10.1016/j.phrs.2017.05.017
• Languages: English
• ISSNs: 1043-6618

Abstract

Graphical abstract: Abstract: The satiety-promoting action of oleoylethanolamide (OEA) has been associated to the indirect activation of selected brain areas, such as the nucleus of the solitary tract (NST) in the brainstem and the tuberomammillary (TMN) and paraventricular (PVN) nuclei in the hypothalamus, where noradrenergic, histaminergic and oxytocinergic neurons play a necessary role. Visceral ascending fibers were hypothesized to mediate such effects. However, our previous findings demonstrated that the hypophagic action of peripherally administered OEA does not require intact vagal afferents and is associated to a strong activation of the area postrema (AP). Therefore, we hypothesized that OEA may exert its central effects through the direct activation of this circumventricular organ. To test this hypothesis, we subjected rats to the surgical ablation of the AP (APX rats) and evaluated the effects of OEA (10 mg kg −1 i.p.) on food intake, Fos expression, hypothalamic oxytocin (OXY) immunoreactivity and on the expression of dopamine beta hydroxylase (DBH) in the brainstem and hypothalamus. We found that the AP lesion completely prevented OEA's behavioral and neurochemical effects in the brainstem and the hypothalamus. Moreover OEA increased DBH expression in AP and NST neurons of SHAM rats while the effect in the NST was absent in APX rats, thus suggesting the possible involvement of noradrenergic AP neurons. These results support the hypothesis of a necessary role of the AP in mediating OEA's central effects that sustain its pro-satiety action.