title: Hypothalamic osmoregulation is maintained across the wake-sleep cycle in the rat.
abstract: In different species, rapid eye movement sleep (REMS) is characterized by a thermoregulatory impairment. It has been postulated that this impairment depends on a general insufficiency in the hypothalamic integration of autonomic function. This study aims to test this hypothesis by assessing the hypothalamic regulation of body fluid osmolality during the different wake-sleep states in the rat. Arginine-vasopressin (AVP) plasma levels were determined following intracerebroventricular (ICV) infusions of artificial cerebrospinal fluid (aCSF), either isotonic or made hypertonic by the addition of NaCl at three different concentrations (125, 250 and 500 mM). Animals were implanted with a cannula within a lateral cerebral ventricle for ICV infusions and with electrodes for the recording of the electroencephalogram. ICV infusions were made in different animals during Wake, REMS or non-REM sleep (NREMS). The results show that ICV infusion of hypertonic aCSF during REMS induced an increase in AVP plasma levels that was not different from that observed during either Wake or NREMS. These results suggest that the thermoregulatory impairment that characterizes REMS does not depend on a general impairment in the hypothalamic control of body homeostasis.
authors.affiliation: Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Luppi
authors.forename: Davide
authors.initials: D
authors.lastname: Martelli
authors.forename: Roberto
authors.initials: R
authors.lastname: Amici
authors.forename: Francesca
authors.initials: F
authors.lastname: Baracchi
authors.forename: Matteo
authors.initials: M
authors.lastname: Cerri
authors.forename: Daniela
authors.initials: D
authors.lastname: Dentico
authors.forename: Emanuele
authors.initials: E
authors.lastname: Perez
authors.forename: Giovanni
authors.initials: G
authors.lastname: Zamboni
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D002555:Cerebrospinal Fluid / Q000502:physiology; D004569:Electroencephalography; D007031:Hypothalamus / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D014851:Wakefulness / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D001127:Arginine Vasopressin