title: Microinjection of the melanin-concentrating hormone into the lateral basal forebrain increases REM sleep and reduces wakefulness in the rat.
abstract: OBJECTIVE
  To examine the effects of bilateral microinjection of melanin-concentrating hormone (MCH) 50 and 100 ng into the horizontal limb of the diagonal band of Broca (HDB) on sleep variables during the light phase of the light-dark cycle of the rat.
  
  
  METHODS
  Male Wistar rats were implanted for chronic sleep recordings. In addition, a guide cannula was implanted above the right and left HDB. Following the microinjection of MCH or control solution the electroencephalogram and the electromyogram were recorded for 6 h. Data was collected and classified as either wakefulness (W), light sleep, slow wave sleep (SWS) or REM sleep (REMS). Latencies for SWS and REMS, as well as the number of REM periods and the mean duration of REM episodes were also determined.
  
  
  RESULTS
  MCH 50 and 100 ng significantly decreased W during the first 2-h of recording. Moreover, MCH 100 ng significantly reduced REMS latency and increased REMS time during the first 2-h block of the recording, due to an increase in the number of REM periods.
  
  
  CONCLUSIONS
  Our findings tend to suggest that the basal forebrain participates in the effects of MCH on W and REMS through the deactivation of cholinergic, glutamatergic and γ-aminobutyric acid (GABA)-ergic cells.
authors.affiliation: Department of Physiology, School of Medicine, Montevideo 11800, Uruguay.
authors.forename: Patricia
authors.initials: P
authors.lastname: Lagos
authors.forename: Jaime M
authors.initials: JM
authors.lastname: Monti
authors.forename: Héctor
authors.initials: H
authors.lastname: Jantos
authors.forename: Pablo
authors.initials: P
authors.lastname: Torterolo
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D004576:Electromyography; D018698:Glutamic Acid / Q000378:metabolism; D007028:Hypothalamic Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008543:Melanins / Q000008:administration & dosage / Q000494:pharmacology*; D008845:Microinjections; D010907:Pituitary Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D016548:Prosencephalon / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012895:Sleep, REM / Q000187:drug effects*; D014851:Wakefulness / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; C019463:melanin-concentrating hormone; D000109:Acetylcholine