Neuroanatomical distribution of MCH in the brain and pituitary of submammalian vertebrates.
Melanin-concentrating hormone (MCH) is a cyclic neuropeptide that has been initially characterized from a salmon pituitary extract and subsequently identified in various species from all classes of vertebrates. The present review summarizes the current knowledge regarding the neuroanatomical distribution of MCH-immunoreactive neurons in submammalian vertebrates. In all species examined, MCH-immunoreactive perikarya are confined to the hypothalamus, with the exception of the cyclostome Lampetra fluvialis and the lungfish Protopterus annectens, in which additional populations of MCH-immunoreactive cell bodies occur in the telencephalon, and the frogs Rana ridibunda and Rana esculenta which exhibit MCH-positive perikarya in thalamic nuclei. In teleosts, in the frog R. ridibunda and in the L. fluvialis, MCH is present in the classical hypothalamic-neurohypophysial system indicating that the peptide may play the role of a neurohormone. In other groups, MCH-immunoreactive nerve fibers are widely distributed in various brain regions suggesting that, in these species, MCH in the central nervous system may act as a neurotransmitter or/and a neuromodulator rather than a neurohormone.
Department of Biology, University of Genova, Italy. mvallari@unige.it
Mauro
M
Vallarino
Federica
F
Bruzzone
Hubert
H
Vaudry
D000663:Amphibians / Q000378:metabolism; D000818:Animals; D001717:Birds / Q000378:metabolism; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism*; D005399:Fishes / Q000378:metabolism; D007028:Hypothalamic Hormones / Q000378:metabolism* / Q000502:physiology; D007031:Hypothalamus / Q000378:metabolism; D008543:Melanins / Q000378:metabolism* / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000502:physiology; D010902:Pituitary Gland / Q000033:anatomy & histology / Q000378:metabolism*; D010907:Pituitary Hormones / Q000378:metabolism* / Q000502:physiology; D012104:Reptiles / Q000378:metabolism; D013687:Telencephalon / Q000378:metabolism
D007028:Hypothalamic Hormones; D008543:Melanins; D018377:Neurotransmitter Agents; D010907:Pituitary Hormones; C019463:melanin-concentrating hormone