GABAergic control of hypothalamic melanin-concentrating hormone-containing neurons across the sleep-waking cycle.
The perifornical-lateral hypothalamic area is implicated in regulating waking and paradoxical sleep. The blockade of GABAA receptors by iontophoretic applications of bicuculline (or gabazine) into the perifornical-lateral hypothalamic area induced a continuous quiet waking state associated to a robust muscle tone in head-restrained rats. During the effects, sleep was totally suppressed. In rats killed at the end of a 90 min ejection of bicuculline, Fos expression was induced in approximately 28% of the neurons immunoreactive for hypocretin and in approximately 3% of the neurons immunostained for melanin-concentrating hormone within the ejection site. These results suggest that neurons containing melanin-concentrating hormone are not active during waking and that the lack of a potent GABAergic influence during waking is consistent with their role in sleep regulation.
Goutagny
Romain
R
CNRS, UMR 5167, Faculté de Medecine, RTH Laennec, 7 rue G. Paradin, 69372 Lyon cedex 08, France.
Luppi
Pierre-Hervé
PH
Salvert
Denise
D
Gervasoni
Damien
D
Fort
Patrice
P
D000818:Animals; D004569:Electroencephalography / Q000379:methods; D018756:GABA Antagonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists; D007028:Hypothalamic Hormones / Q000502:physiology*; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008543:Melanins / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010907:Pituitary Hormones / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000502:physiology*; D012894:Sleep Stages / Q000187:drug effects / Q000502:physiology*; D014851:Wakefulness / Q000187:drug effects / Q000502:physiology*
D018756:GABA Antagonists; D058787:GABA-A Receptor Antagonists; D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D011963:Receptors, GABA-A; C019463:melanin-concentrating hormone