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.     

Influence of brown adipose tissue on deep cervical temperature during sleep in the young rabbit

Summary In young rabbits the slope of the temperature in the deep cervical region close to brown adipose tissue increased during desynchronized sleep at low ambient temperature. No increase occurred at neutral ambient temperature. In control rabbits (after disappearance of brown adipose tissue), the slope of deep cervical temperature did not increase during desynchronized sleep at low or neutral ambient temperatures.Preliminary data were reported at the Association des Physiologistes, Réunion de Poitiers, 20–23 June 1983.Acknowledgments. We wish to thank Giuseppe Mancinelli and Leonida Sabattini for technical assistance. This work was supported by a grant from the Consiglio Nazionale delle Ricerche, Rome. J.P.L. wishes to thank NATO for partial financial support during his stay at the Physiology Department in Bologna.     

Early changes of cyclic nucleotide levels in a mitogenic reaction in the rat mesentery

Summary By measuring simultaneously cAMP and cGMP we found a biphasic time course with regard to cGMP and the cGMP/cAMP ratio very early in a mitogenic reaction in vivo. This is a new finding.This work was supported by the Swedish Cancer Society and the Swedish Medical Research Council (project No. 04X-04498). We are indebted to Marcela Bartonek and Margareta Odenö for expert technical assistance and to Erik Leander for help with statistical matters.     

Effect of dibutyryl cyclic AMP and analogs on the rate of contractions of myocytes in culture

Summary ²O,⁶N-butyryl, 3, 5-cyclic monophosphate (dibu cAMP) when added to fetal rat heart cells in culture inhibits myocyte contraction. This inhibition is 100, 84 and 51% complete when the dibu cAMP concentration used is 2, 0.2 and 0.02 mM, respectively. The potency of dibu cAMP derivatives in myocyte contraction inhibition follows the order, dibu cAMP> ⁶N-bu cAMP> ²O-bu cAMP=AMP>butyrate. The inhibition caused by the first three chemicals is greater than 70%.The author was a Moss Heart Fellow and acknowledges the technical assistance of Ms Martha Peet. This work was supported in part by the American Heart Association, National Science Foundation and American Cancer Society.     

Adenosine-3,5-phosphate levels in brain structures of rats submitted to four different behavioral procedures

Summary Shuttle avoidance training decreased the cAMP content of rat brain (excluding hippocampus and caudate nucleus), amygdala and hypothalamus. Stimulation by tones alone had a similar effect, but only in the brain fraction. Pseudoconditioning or footshocks alone had no effect.With support from FAPERGS, CNPq, and PROPESP-UFRGS, Brasil. We are grateful to Miss Sonia Eisinger for her valuable technical assistance.     

Timing of mitosis in Physarum polycephalum: Effects of agents affecting cyclic AMP concentrations

Summary Cultures ofPhysarum polycephalum incubated with caffeine or theophylline for over 100 min prior to mitosis exhibited mitotic delay proportional to the time of treatment before 100 min. Starved cultures exhibited mitotic delay at times of starvation longer than 180 min and slight stimulation from 100–180 min. Dibutyryl cAMP appeared to accelerate reconstruction of the nucleus following mitosis.Acknowledgments. The authors wish to express their appreciation to Dr. Volker Vogt and Dr. Richard Threlfall for helpful discussions, to Kathryn Behrens for able technical assistance and to the European Molecular Biology Organization for a short-term fellowship to J. R. T. during the course of this work. Supported by grant 3.501.75 of the Swiss National Science Foundation.     

Sleep in the tortoiseKinosternon sp.

Summary Individuals ofKinosternon sp., previously confined to laboratory conditions, were chronically implanted with electrodes for electroencephalogram, electro-oculogram and electrocardiogram recording. Behavioral states of waking and sleep were clearly observed. Two sleep stages were present: quiet sleep and REM or active sleep. Electrical cerebral activity was polymorphic and irregular. EEG frequencies declined and amplitudes diminished with sleep. Arrhythmic spikes occurred during behavioral sleep and declined with waking. Heart rate decreased when passing from wakefulness to quiet sleep. It was slightly but consistently higher during active sleep compared with quiet sleep.     

Enhancement of ethanol-induced sleep by whole oil of nutmeg

Summary In young chickens, the whole oil of nutmeg (200 mg/kg) increased the duration of sleep induced by ethanol (1–4 g/kg), particularly deep sleep. Inproniazid (50–400 mg/kg), a monoamine oxidase inhibitor, did not mimic this effect.Acknowledgments. The authors would like to thank Mr E.J. Spellman of Frische-D & O for supplying the oil of nutmeg and Mrs N. Sherry for secretarial and editorial assistance.     

EEG and sleep in aged hospitalized patients with senile dementia: 24-h recordings

Polygraphic recordings of wake and sleep were performed on 10 partly bed-ridden, severely deteriorated patients with senile dementia. Compared with healthy elderly persons these subjects showed less SWS (slow wave sleep, characterized by high amplitude, slow EEG waves), less REM sleep (rapid eye movement sleep, usually accompanied by dream activity) and poorly organized stage 2 sleep (no sleep spindles, i.e. phasic EEG activity with a frequency of 12-14 Hz). Six of the 10 patients had no dominant alpha rhythm during wakefulness; this seemed to be related to their more deteriorated clinical state, to still less SWS and REM sleep and more time spent in stage 2. The basic NREM-REM cycle of sleep, i.e. the regular alternation between non-REM- and REM-periods, could still be distinguished, however, and showed similar average temporal characteristics as in healthy old and younger people. Similarly, although sleep was severely fragmented in most patients and many sleep episodes occurred during the day, the day-night alternation of wakefulness and sleep was maintained in the sample as a whole.     

Somesthetic cortex reactivity during sleeping and waking in the rat

Summary The cortical S1 responsiveness was studied by unique and coupled stimuli of non-maximal intensity applied to somesthetic radiations. The reactivity is highest during sleep with slow waves, lowest during active waking, intermediate during non-active waking and rapid sleep. The recovery of responsiveness presents an exactly opposite form and begins at a long interstimulus delay (>150 msec).     

Intracellular cyclic AMP in vesicular stomatitis or Senda? virus infected cells (author's transl)

In KB cells, MRC5 and adult skin fibroblasts infected by low doses of Senda? virus, intracellular cyclic AMP levels rose and fell in the first hours following infection, then remained lower than basal level during at least 2 days in KB cells and adult skin fibroblasts. When compared to other viruses or cAMP inducers previously described, this effect appeared specific of Senda? virus. Mechanisms and roles of cAMP variations are discussed. VSV-infected KB cells showed slightly decreased cAMP levels during the first hours following infection.     

Forskolin inhibits tension development in detergent-treated cardiac muscle fibers

Summary In detergent-treated cardiac muscle fibers, forskolin, a potent activator of adenylate cyclases, inhibits tension development elicited with submaximal [Ca²⁺] and increases incorporation of³²P into troponin-I. A similar reduced tension development has been observed after treatment with cAMP or the catalytic subunit of the cAMP-dependent protein kinase. It is concluded that these fibers still contain much of the enzyme cascade involved in evoking a contractile response to \-adrenergic stimulation.Acknowledgment. The authors thank Dr H. Metzger, Hoechst AG, Frankfurt (FRG) for the gift of forskolin. The excellent technical assistance of Mrs Doris Eubler and the support by the Deutsche Forschungsgemeinschaft (SFB 90) are gratefully acknowledged.     

Diurnal change in stature: effects of sleep deprivation in young men and middle-aged men

Sleep deprivation was associated with decreased stature and it blunted the normal 24-h rhythm in young and in middle-aged men. Loss in stature was regained during the first recovery night of sleep. The 24-h rhythm in height is not an endogenous circadian rhythm but depends upon the periods of recumbency over the sleep/wake cycle.     

Einfluss von elektrischer Stimulation auf Phosphorylase-Aktivität und cAMP-Gehalt in Insektenflugmuskeln vonLocusta migratoria

Summary In half-thorax ofLocusta migratoria, the activity of phosphorylases and the level of cAMP was studied during electrical stimulation of flight muscles. Both phosphorylase activity and cAMP level increased during phasic and tetanic contractions but no exact correlation could be found.

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Der benutzte Szintillationszähler wurde aus Mitteln des Landesamtes für Forschung, Düsseldorf angeschafft.     

Diurnal change in stature: effects of sleep deprivation in young men and middle-aged men

Summary Sleep deprivation was associated with decreased stature and it blunted the normal 24-h rhythm in young and in middle-aged men. Loss in stature was regained during the first recovery night of sleep. The 24-h rhythm in height is not an endogenous circadian rhythm but depends upon the periods of recumbency over the sleep/wake cycle.Acknowledgments. The first author was a Medical Research Council scholar; the second was supported by the Scottish Hospital Endowments Research Trust.     

Inhibitory effect of fasting on the glucagon-induced increase of liver phosphorylase A activity in rats

Summary The increase of liver phosphorylase A activity observed 1, 2 and 3 min after i.v. administration of 0.1 g kg^–1 glucagon to fed rats was found to be completely absent in 24 h fasted animals, although there is even an exaggerated liver cAMP response to glucagon after fasting.Acknowledgments. We would like to thank Mrs M. Fritzová and Mr F. Kovai for expert technical assistance.     

Tele-encephalic versus cerebellar control upon ponto-geniculo-occipital waves during paradoxical sleep in the cat

Summary Studying the effects that removal of the cerebellum and the frontal lobes had upon the phasic activities (PGO waves) of paradoxical sleep in the cat, it is shown that in this phase of the sleep-wakefulness cycle the cerebellum exerts an inhibitory action upon the amplitude of the GPO, while the frontal lobes influences the pattern of their discharges.This work was supported by Centro Nacional Ramon y Cajal de la Seguridad Social, Madrid, Spain.Acknowledgment. I am very grateful to Miss.M. Azuara for her technical assistance.     

The mechanical and biochemical effects of pentoxifylline on the perfused rat heart

Summary Perfusion of the isolated rat heart at constant heart rate and coronary flow with the inhibitor of cyclic nucleotide phosphodiesterase, pentoxifylline (10^–4 moles/l), produced no significant effect on the maximum rate and the peak of contraction, but increased the maximum rate of relaxation. cAMP level and cAMP-dependent protein kinase activity were increased in the absence of changes in cGMP. The results were identical in hearts of reserpinized rats.This work was supported by grants from the Consejo Nacional de Investigaciones Cientificas y Técnicas and the Comisión de Investigaciones Científicas. Buenos Aires, Argentina.We thank Hoechst Laboratories for the partial support and Mrs Alicia R. Ramirez and María Prinzo for the excellent technical assistance.     

Skinned smooth muscle: Time course of force and ATPase activity during contraction cycle

Summary The time course of ATPase activity and force has been determined during contraction and relaxation in skinned (hyperpermeable) anterior byssus retractor muscle, ABRM, ofMytilus edulis and compared with corresponding measurements on skinned taenia coli of guinea-pigs. Following a calcium-induced contraction, lowering the [Ca⁺⁺] to 10^–8 M rapidly reduces ATPase activity within 2 min to resting levels while force declines only to about 30–50% of maximal tension within the same time. Thus slow relaxation is due to a catch-like-state which is common to different kinds of smooth muscles and can be reduced with cAMP in ABRM and by P_i in taenia coli.The support by the Deutsche Forschungsgemeinschaft and the excellent technical assistance of Mrs K. Winnikes are gratefully acknowledged.     

Experimental dissociation between hippocampal theta activity in wakefulness and hippocampal theta activity in paradoxal sleep in the rat]

The effects of electrolytic lesion of the septum on the theta activity of the dorsal hippocampus were studied in the chronically implanted Rat during wakefulness and paradoxical sleep. The experimental results show that depending on its localization, septal lesion can either: (1) eliminate the wakefulness theta rhythm without suppressing that of paradoxical sleep; (2) eliminate the paradoxical sleep theta rhythm without suppressing that of wakefulness. These results suggest that there are two kinds of theta activity having different anatomophysiological bases and a different functional significance: one associated with wakefulness and the other with paradoxical sleep.