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Effet de la pine´alectomie sur lese´tats et rythmes de sommeil du rat maˆle

1974; Elsevier BV; Volume: 81; Issue: 1 Linguagem: Francês

10.1016/0006-8993(74)90480-6

1872-6240

J Mouret, J. Coindet, Guy Chouvet,

Sleep and related disorders

Les effets de la pine´alectomie sur lese´tats et rythmes de sommeil onte´te´e´tudie´s sur 7 rats enregistre´s de manie´re continue (24 h sur 24) pendant les 8 jours pre´ce´dant et les 30 jours suivant la pine´alectomie, la pe´riodicite´de l'e´clairement (12/12), restant inchange´e. Apre`s pine´alectomie, re´alise´e sur les rats déja`implantés sans toucher aux sinus veineux, les variations nycthéme`rales du sommeil lent (SL) et du sommeil paradoxal (SP), pre´sentent une dissociation. Il n'existe pas de variation des quantite´s de SP ou de SL par 24 h, mais les quantite´s de SP sont re´duites pendant la pe´riode d'e´clairement et augmente´es pendant la pe´riode d'obscurite´. Les variations diurnales et circadiennes du SL conservent les caracte´ristiques des enregistrements de controˆle avec un spectre important pour une pe´riodicite´de 24 h. Par contre la pe´riodicite´circadienne du SP est pratiquement abolie. Nos re´sultats sugge´rent que la pine´ale puisse jouer un roˆle important dans l'organisation nycthéme`rale et circadienne du SP, ainsi que dans son couplage avec le SL. The effects of pinealectomy on paradoxical sleep (SP) and slow-wave sleep (SL) have been studied in rats maintained with a 12/12 light-dark schedule. Continuous recordings (24 h/day) from cerebral cortex and neck muscles were used to monitor SL, SP and arousal in the same 7 male rats during 8 days before and 30 days after pinealectomy. The technique of pinealectomy spares the venous sinuses and can be performed on already implanted rats. Following pinealectomy, a dissociation developed between the nyctohemeral variations of SP and SL. There were no changes in the amount of SP and SL on a 24-h base but SP decreased during the light phase of the cycle and increased during the dark phase. The diurnal variations in SL were normal. The circadian variations in SL remained as in control conditions with high spectrum values for a 24-h periodicity. In contrast to this the circadian periodicity of SP was almost abolished. Our data suggest that the pineal organ can play an important role in the diurnal and circadian organization of SP and its phase relationships with SL.