title: Hypothalamic proopiomelanocortin (POMC) neurons have a cholinergic phenotype.
abstract: Neuronal networks originating in the hypothalamic arcuate nucleus play fundamental roles in the control of energy balance. Neuropeptide Y (NPY)-producing neurons in the arcuate nucleus stimulate food intake, whereas arcuate nucleus neurons that release the proopiomelanocortin (POMC)-derived peptide alpha-melanocyte-stimulating hormone (alpha-MSH) potently reduce food intake. Relatively little attention has been focused on classical neurotransmitters in regulation of food intake. Here, we have investigated the potential presence of acetylcholine (ACh) in NPY- and POMC-containing neuronal populations of the arcuate nucleus. Antisera to proteins required for cholinergic neurotransmission, including choline acetyltransferase (ChAT) and the vesicular acetylcholine transporter (VAChT), were employed in double-labeling immunohistochemical experiments. In colchicine-treated rats, ChAT- and VAChT-immunopositive cell bodies were located in the ventral aspect of the arcuate nucleus. ChAT and VAChT immunoreactivities were demonstrated in alpha-MSH- and cocaine- and amphetamine-regulated transcript (CART)-containing cell bodies of the arcuate nucleus, whereas cell bodies containing NPY or agouti-related peptide (AGRP) were distinct from VAChT-immunoreactive neuronal perikarya. VAChT immunoreactivity was also present in a large number of alpha-MSH-containing nerve fiber varicosities throughout the central nervous system. In the commissural part of the nucleus tractus solitarius, no alpha-MSH-containing cell bodies were found to have ChAT or VAChT immunoreactivity. The presence of markers for cholinergic neurotransmission in a subpopulation of hypothalamic POMC/CART neurons suggests co-release of ACh with peptides derived from the POMC precursor and CART. The results indicate a role for ACh in control of energy balance, mediating the effects of peripheral hormones such as leptin and insulin.
authors.affiliation: Department of Neuroscience, The Retzius Laboratory, Karolinska Institutet, SE-17177 Stockholm, Sweden. bjorn.meister@ki.se
authors.forename: Björn
authors.initials: B
authors.lastname: Meister
authors.forename: Burçak
authors.initials: B
authors.lastname: Gömüç
authors.forename: Elisabet
authors.initials: E
authors.lastname: Suarez
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ishii
authors.forename: Katrin
authors.initials: K
authors.lastname: Dürr
authors.forename: Linda
authors.initials: L
authors.lastname: Gillberg
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009478:Neuropeptide Y / Q000378:metabolism; D010641:Phenotype; D011333:Pro-Opiomelanocortin / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D050494:Vesicular Acetylcholine Transport Proteins / Q000235:genetics / Q000378:metabolism; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; C493461:Slc18a3 protein, rat; D050494:Vesicular Acetylcholine Transport Proteins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D011333:Pro-Opiomelanocortin; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine