MELANIN-CONCENTRATING HORMONE INPUTS TO THE NUCLEUS ACCUMBENS ORIGINATE FROM DISTINCT HYPOTHALAMIC SOURCES AND ARE APPOSED TO GABAERGIC AND CHOLINERGIC CELLS IN THE LONG-EVANS RAT BRAIN

Author(s)

Haemmerle, C. A. S. ^[1] ; Campos, A. M. P. ^[2] ; Bittencourt, J. C. ^{[3, 1]}

Affiliation

^[1] Univ Sao Paulo, Lab Chem Neuroanat, Dept Anat, Inst Biomed Sci, BR-05508000 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05508000 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Inst Psychol, Ctr Neurosci & Behav, BR-05508000 Sao Paulo - Brazil

• Document type: Journal article
• Source: Neuroscience; v. 289, p. 392-405, MAR 19 2015.
• Web of Science Citations: 6

Abstract

Melanin-concentrating hormone {[}MCH] is a neuropeptide that modulates several behaviors, such as feeding and reward. Because the hedonic and rewarding features of a food also influence feeding behavior, the nucleus accumbens {[}Acb] has been highlighted as a key area integrating these roles. Functional data confirm that MCH acts on a subdivision of the Acb; however, considering the importance of finding anatomical and neurochemical data that correlate the previously demonstrated function of MCH, we delineated this investigation based on the following points: (1) Is there a pattern of innervation by MCH fibers regarding the subregions within the Acb? (2) Specifically, which hypothalamic nuclei synthesize MCH and innervate the Acb? (3) Finally, what are the neurochemical identities of the accumbal neurons innervated by MCH inputs? We examined the MCH immunoreactivity {[}MCH-ir] in the Acb in rat brains using the peroxidase technique. Additionally, after injecting retrograde neuronal tracer {[}Fluoro-Gold(R) = FG(R)] into subdivisions of the Acb {[}shell or core], we mapped single-or double-labeled cells. Moreover, using a double immunoperoxidase protocol, we investigated the MCH-ir fibers for gamma-aminobutyric acid {[}GABA]-ir and choline acetyltransferase {[}ChAT]-ir cells in the shell subdivision of the Acb {[}AcbSh]. We found that the MCH-irfibers preferentially innervate the medial AcbSh, particularly the septal pole. This innervation originated from the incerto-hypothalamic area {[}IHy], internuclear area, lateral hypothalamic area, perifornical area, periventricular nucleus and posterior hypothalamus. Moreover, the IHy has the highest relationship between double/single retrogradely labeled cells {[}n = 5.33 +/- 0.66/16 +/- 0.93, i.e. 33.33%] in the whole hypothalamus. Furthermore, our data suggest that MCH-ir fibers are in apposition to GABAergic and cholinergic cells in the AcbSh. Therefore, we provide anatomical support to the ongoing functional studies investigating the relation among the hypothalamus, MCH transmission into the Acb and the involvement of known neuronal phenotypes within the AcbSh. (C) 2015 IBRO. Published by Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 07/56975-9 - Study of melanin-concentrating hormone (MCH) immunoreactive inputs of nucleus acumbens, in rats Long-Evans
• Grantee: Carlos Alexandre dos Santos Haemmerle
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 04/13849-5 - Peptidergic pathways involved in the organization of feeding behavior
• Grantee: Jackson Cioni Bittencourt
• Support Opportunities: Research Projects - Thematic Grants