The orthodox-paradoxical sleep cycle in the rat

Summary Under the postulated existence of a mechanism regulating the NREM sleep-REM sleep sequence and a reset of this mechanism by long awakenings, the variability of sleep cycle in the rat was studied. Awakenings of various durations were included in the definition of sleep cycle boundaries. Results show that an intervening awakening of 1 min is close to the limit under which the same cycle seems to be resumed after the awakening and above which the previous cycle is abortive and a new cycle will start after the next sleep onset.     

The effect of haloperidol on the sleep cycle of the cat

Résumé L'effet de l'halopéridol sur le cycle sommeil/veille a été étudié sur des chats adultes porteurs d'électrodes chroniquement implantées pour l'enregistrement de l'EEG, EMG et des mouvements des yeux. L'halopéridol a fait augmenter d'une manière significantive l'indice de sommeil à ondes lentes. Il a produit l'apparition tardive de la première période de mouvements oculaires rapides (REM) en réduisant le nombre de périodes et l'indice du sommeil REM.     

Excitability changes during paradoxical sleep in the rat

Résumé Le passage de la phase de sommeil avec ondes lentes à la phase ?paradoxale? et souvent aussi du sommeil paradoxal à l'éveil, sont accompagnés chez le rat d'un commencement ou d'une accentuation de l'activité dite ?spindling? dans l'écorce. Des changements phasiques de la fréquence des ondes ϑ dans l'hippocampe se produisirent pendant les périodes paradoxales. Nous n'avons pas remarqué de corrélations entre ces phénomènes.

---

---

This work was supported in part by the US Public Health Service (grant NB-01883) and in part by the US Air Force Office of Scientific Research (grant AF-AFOSR 246-63).     

Influence of long-lasting stimulation of the caudate nuclei on sleep cycle in rats

Zusammenfassung Die telencephalische Schlafphase der Ratte kann bei lang dauernder elektrischer Nucleuscaudatus-Reizung deutlich verkürzt werden.     

Sex steroids in the rat submaxillary gland during the estrus cycle

Relatively high progestagen levels were found in female rat submaxillary glands, with a maximum in the proestrus stage at 22 h and 2 minima; in proestrus between 10 and 14 h, and in estrus at 14 h. Estrogen and androgen concentrations in the gland were undetectable during most of the cycle except in the proestrus stage, when the highest level was determined at 14 h for estrogens and at 17 h for androgens.     

Brain nucleic acid content during the estrous cycle in the rat

Résumé Le contenu total du RNA, DNA et le poids sec de certaines parties prélevées au cerveau sont resté constants durant les différentes étapes du cycle oestral.

---

---

Deceased.     

Uterine secretion during the sexual cycle in the rat and its capacity to disperse corona cells in vitro.

It was found that closure of the uterus disturbed the first 2 cycles after the operation; thereafter the normal cycle was resumed. The quantity of uterine fluid was increased at pro-oestrus and oestrus and reduced at met-oestrus and di-oestrus. Slight inverse changes in viscosity were observed. There was no significant difference in the pH. The corona-cell dispersing factor seems to be an oestrogen-dependent constituent of uterine secretion.     

Seasonality in human sleep.

The timing of sleep and sleep EEG parameters in 10 healthy male subjects were investigated in four seasons under controlled conditions. The phase of nocturnal sleep was delayed about one and a half hours in winter as compared to that in summer. The duration of stage 4 sleep decreased and REM sleep increased significantly in winter compared with summer. The seasonality in the timing of sleep can be explained by photoperiodic time cues, but the changes in sleep EEG parameters are difficult to explain in terms of photoperiod.     

Glutathione and gamma-glutamyl cycle enzymes in rat mammary gland

The main enzymes of the gamma-glutamyl cycle during the lactogenic cycle in rat mammary gland were studied. A significant increase was found in all of them with the onset of lactogenesis. The effect of methionine sulfoximine on reduced glutathione concentration was studied in tissue slices of lactating mammary gland. The findings suggest that this compound effects glutathione synthesis by inhibiting gamma-glutamylcysteine synthetase.     

Changes in cAMP concentration in the rat preoptic area during synchronized and desynchronized sleep

Summary cAMP concentration was found to be significantly lower during desynchronized sleep than during synchronized sleep in the preoptic area of rats kept at normal laboratory temperature. No significant changes in cerebral cortex cAMP concentraion were observed in the same experimental conditions.This work was supported by grants from Consiglio Nazionale delle Ricerche and Ministero della Pubblica Istruzione.The authors wish to thank G. Mancinelli and L. Sabattini for technical assistance and M. Luppi for secretarial assistance.     

The influence of the rostropontine-ventrolateral region on the sleep-wakefulness cycle.

Lesions affecting the ventrolateral area of the nucleus reticularis pontis oralis produced, in chronic implanted cats, a significant decrease of paradoxical sleep.     

Changes in cAMP concentration in the rat preoptic area during synchronized and desynchronized sleep

cAMP concentration was found to be significantly lower during desynchronized sleep than during synchronized sleep in the preoptic area of rats kept at normal laboratory temperature. No significant changes in cerebral cortex cAMP concentration were observed in the same experimental conditions.     

Inbreeding considerations in a REM sleep model for rat swimming activity

Over the past few years, our laboratory group has elaborated a repeated measures rat swimming test. It provides an animal base for showing that the REM sleep mechanism is important to both emotional responsiveness and environmental adaptations. All of that work has been done with Sprague-Dawley rats obtained from a local supplier. Work done with two European rat stocks (by researchers in France and The Netherlands) shows general agreement with our own. In this presentation, we directly compare rats derived from an English vendor's Sprague-Dawley stock with the U.S. based Sprague-Dawley stock which we have been using. We also make strain comparisons via the F344 and the Long Evans strains. Although the literature has numerous examples of swimming test differences between inbred and wild rat stocks, strain difference effects have not been reported. We report that there are significant differences attributable to inbred strain but not to vendor on this measure.     

Inbreeding considerations in a REM sleep model for rat swimming activity

Summary Over the past few years, our laboratory group has elaborated a repeated measures rat swimming test. It provides an animal base for showing that the REM sleep mechanism is important to both emotional responsiveness and environmental adaptations. All of that work has been done with Sprague-Dawley rats obtained from a local supplier. Work done with two European rat stocks (by researchers in France and The Netherlands) shows general agreement with our own. In this presentation, we directly compare rats derived from an English vendor's Sprague-Dawley stock with the U.S. based Sprague-Dawley stock which we have been using. We also make strain comparisons via the F344 and the Long Evans strains. Although the literature has numerous examples of swimming test differences between inbred and wild rat stocks, strain difference effects have not been reported. We report that there are significant differences attributable to inbred strain but not to vendor on this measure.Supported by NIH/MBRS Grant 08192. Student coworkers who received program support were: D. Gillham, E. Hannas, M. Ochoa, and J. Lopez. N. Phillips made the figure.