Rat diencephalic neurons producing melanin-concentrating hormone are influenced by ascending cholinergic projections.
Innervation of diencephalic neurons producing melanin-concentrating hormone by choline acetyltransferase-containing axons was examined using double immunohistochemistry. In the rostromedial zona incerta and perifornical regions of the lateral hypothalamic area, many choline acetyltransferase-positive fibers were detected in the immediate vicinity of melanin-concentrating hormone perikarya and their proximal dendrites. Putative contact sites were less abundant in the far lateral hypothalamus, and only scattered close to the third ventricle. After injections of the retrograde tracer FluoroGold, most of these projections appeared to originate in the pedunculopontine and laterodorsal tegmental nuclei. Finally, to determine the putative effect of acetylcholine on the melanin-concentrating hormone neuron population, the cholinergic agonist carbachol was added to the medium of hypothalamic slices in culture. Using competitive reverse transcriptase-polymerase chain reaction, carbachol was found to induce a rapid increase in the melanin-concentrating hormone messenger RNA expression. This response was abolished by both atropine, a muscarinic antagonist, and hexamethonium, a nicotinic antagonist. Thus, the bulk of these results indicates that the diencephalic melanin-concentrating hormone neurons are targeted by activating ascending cholinergic projections.
Bayer
L
L
CNRS ESA 6025, Laboratoire d'Histologie, Embryologie, Cytogénétique, CNRS FR 51 Institut d'Etude et de Transfert de Gènes, Faculté de Médecine et de Pharmacie, Besançon, France.
Risold
P Y
PY
Griffond
B
B
Fellmann
D
D
D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D018678:Cholinergic Agents / Q000494:pharmacology; D002799:Cholinergic Fibers / Q000502:physiology*; D004027:Diencephalon / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D007028:Hypothalamic Hormones / Q000096:biosynthesis* / Q000235:genetics; D007150:Immunohistochemistry; D008297:Male; D008543:Melanins / Q000096:biosynthesis* / Q000235:genetics; D009474:Neurons / Q000201:enzymology / Q000378:metabolism*; D010907:Pituitary Hormones / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009435:Synaptic Transmission / Q000502:physiology*; D014018:Tissue Distribution / Q000502:physiology
D018678:Cholinergic Agents; D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D012333:RNA, Messenger; C019463:melanin-concentrating hormone; D002795:Choline O-Acetyltransferase