Effects of Intraventricular Implantation of Crystalline Estradiol Benzoate on the Sleep‐Wakefulness Orcadian Rhythm of Ovariectomized Rats

Abstract

The effect of estrogen on the sleep‐wakefulness circadian rhythm was examined in ovariectomized rats. Implantation of crystalline estradiol benzoate (EB) into the third cerebral ventricle reduced the slow wave sleep (SWS) and paradoxical sleep (PS) appearances within the dark period. This result was similar to that obtained by a systemic administration of 20 μg of EB. The inhibition of sleep during the nighttime was more remarkable in PS than in SWS. The reduction of SWS was due to a shorter duration of SWS episodes and the reduction of PS to a fewer number of PS episodes. These results indicate that ovariectomized rats treated with estrogen develop an inability to sustain episodes of SWS and initiate PS episodes.

Female Reproductive Hormones Alter Sleep Architecture in Ovariectomized Rats

“…Among previous studies of estradiol effects on sleep, only a few have examined sleep architecture in detail, and these have used various forms of estradiol and treatment strategies. Our results, using the natural 17 β-estradiol, are consistent with those in studies that used estradiol benzoate, 19,21 but not with the results of one study 31 using 17α-ethinyl estradiol (both are synthetic estrogens that are metabolized at a much slower rate than the natural 17 β-estradiol). In the latter study, when OVX rats were treated systemically with 4 daily injections of 17α-ethinyl estradiol, the duration but not the number of REMS episodes was decreased during the dark phase.…”

“…These findings on baseline sleep were largely consistent with a number of previous studies which reported that subcutaneous injections of estradiol reduced spontaneous REMS amounts in OVX rats. [19][20][21][22] Decreases in sleep, in particular REMS, have also been observed in intact female rats on the proestrus night (i.e., after spontaneous estradiol and progesterone peaks). [23][24][25] However, in contrast to our previous results, a few studies have shown only minor changes during the estrous cycle in sleep recovery after 6 h of sleep deprivation in rats 25 and little effect of endogenous or exogenous estradiol on sleep homeostasis in mice.…”

Estradiol replacement enhances sleep deprivation-induced c-Fos immunoreactivity in forebrain arousal regions of ovariectomized rats

“…Behavioral observations of nondeprived animals indicated that E 2 administration had no effect on sleep and wake states during a 2-h observation period in the light phase: all animals appeared to be asleep most of the time. Previous studies reported that E 2 replacement increased wakefulness and decreased sleep (especially rapid eye movement sleep) most robustly during the dark phase (8,46,57). The brief observation period during the light phase in this study may not have been adequate to reveal any behavioral effects.…”

Geschlechtsspezifische Unterschiede der schlafendokrinen Regulation und deren Bedeutung für die Pathophysiologie der Major Depression

“…Östrogene die GABA-A Rezeptorexpression und die GABA Freisetzung positiv beeinflussen (Herbison et al 1989;Herbison and Fenelon 1995 (Branchey et al 1971;Leibenluft 1993;Matsushima and Takeichi 1990 (Ferrini et al 1999;Redei et al 1994 (Born et al 1995;Heuser et al 1994;Seeman et al 1995 Kortisol-und ACTH-Sekretion zeigten (Born et al 1995;Van Cauter et al 1996 (Mirmiran et al 1992;Swaab 1995;Van Someren 2000).…”