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.     

Measurement of cyclic AMP in the islets of Langerhans of newborn rats. Effect of amino acids]

Radioimmunoassay of cyclic AMP (cAMP) in the islets of Langerhans from 48-64 h old Rats was performed after succinylation of the samples. cAMP was detected at 0.03 nM. The cAMP content of islets increases when L-arginine, L-lysine and L alanine are added together in the incubation medium at a concentration of 5-10 mM each. When phosphodiesterase is inhibited by theophylline the three amino acids considerably increase the cAMP content of islets. Thus an increase in cAMP content of the islets was observed with a concentration of amino acids which is efficient in stimulating the insulin and glucagon secretion.     

Adenylate cyclase activation and its effects on intracellular cAMP in infected KB cells during trypsin-induced infectious Senda? virus production (author's transl)]

KB cells infected by Senda? virus can produce infectious virus if they are trypsinated twice over 24 h. Adenylate cyclase activity in infected KB cells is higher and more strongly activated by trypsin than that of control cells, but intracellular concentration of cAMP is the same, except during a short time after trypsinations, especially after the second trypsination which causes infectious virus production. During this short time, intracellular cAMP is slightly higher in infected cells. This miseffect of adenylate cyclase activation on intracellular cAMP concentrations might be related to an increased cell permeability caused by trypsin.     

Activation de l'adénylate cyclase et ses répercussions sur le taux intracellulaire d'AMP cyclique dans les cellules KB infectées produisant du virus Sendaï, infectieux sous l'influence de la trypsine

Summary KB cells infected by Sendaï virus can produce infectious virus if they are trypsinated twice over 24 h. Adenylate cyclase activity in infected KB cells is higher and more strongly activated by trypsin than that of control cells, but intracellular concentration of cAMP is the same, except during a short time after trypsinations, especially after the second trypsination which causes infectious virus production. During this short time, intracellular cAMP is slightly higher in infected cells. This miseffect of adenylate cyclase activation on intracellular cAMP concentrations might be related to an increased cell permeability caused by trypsin.     

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

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 greater than 6N-bu cAMP greater than 2O-bu cAMP = AMP greater than butyrate. The inhibition caused by the first three chemicals is greater than 70%.     

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.     

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.     

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.     

Effects of several preoperative medications on fat cell lipolysis, and activity of adipose tissue cyclic AMP phosphodiesterase.

Effects were examined of atropine, diazepam, pethidene, promethazine, scopolamine, omnopon and papaverine on basal and noradrenaline-stimulated lipolysis in rat isolated fat cells and on rat adipose tissue cyclic AMP phosphodiesterase activity. Papaverine at high concentration (1 mM) inhibited both basal and hormone-stimulated lipolysis, whereas diazepam enhanced basal lipolysis. At a 'clinical dose', omnopon increased both basal and noradrenaline-stimulated lipolysis. Adipose tissue cAMP phosphodiesterase activity was strongly inhibited by 1 mM diazepam, papaverine, promethazine and omnopon (280 microgram ml-1). Lack of enhancement of lipolysis by the established cAMP phosphodiesterase antagonist papaverine, is compatible with simultaneous inhibition also of adipose adenyl cyclase. Diazepam-stimulated lipolysis is compatible with its phosphodiesterase inhibitory activity. It is proposed that papaverine-containing omnopon may offer some survival advantages during surgical stress by facilitating a caloric supply.     

The reversal of glucose repressed prodigiosin production inSerratia marcescens by the cyclic 3′5′-adenosine monophosphate inhibitor theophylline

Summary Glucose was found to cause severe repression of prodigiosin production inSerratia marcescens and a dose related partial reversal was demonstrated by theophylline. It is suggested that this reversal is due to the inhibition of cAMP phosphodiesterase and the concomitant increase in cellular cAMP concentration.     

Increase of interferon antiviral activity by exogenous cyclic adenosine-3':5'-monophosphate (cAMP).

Some effects of cAMP on replication of Semliki Forest Virus in chick embryo fibroblast cell cultures are described. Depending on concentration, the incorporation of [3H]-uridine into viral RNA or the formation of plaque-forming units is inhibited; the highest concentration tested was 8 mM. Cyclic AMP has an effect of its own and increases the Interferon action in the lower concentration ranges of Interferon (up to 1 unit/ml). The effect of cyclic AMP is fast, needs no induction and is also visible in late phases of viral replication. However, these experiments do not establish a causal relation between cAMP and Interferon.     

The inhibitory effect of paraquat on histamine and isoproterenol induced changes of cyclic nucleotides in rat lung slices.

The incubation of rat lung slices with paraquat ion (10(-4) M) had no effect on cAMP and cGMP levels of the rat lung slices. The preincubation with the same concentration of paraquat inhibited the cAMP elevating effect of histamine (10(-5) M) and isoproterenol (10(-5) M) and reduced the cGMP level to approximately 50% of the level obtained without preincubation with paraquat.     

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.     

Increase of interferon antiviral activity by exogenous cyclic adenosine-3′∶5′-monophosphate (cAMP)

Summary Some effects of cAMP on replication of Semliki Forest Virus in chick embryo fibroblast cell cultures are described. Depending on concentration, the incorporation of [³H]-uridine into viral RNA or the formation of plaqueforming units is inhibited; the highest concentration tested was 8 mM. Cyclic AMP has an effect of its own and increases the Interferon action in the lower concentration ranges of Interferon (up to 1 unit/ml). The effect of cyclic AMP is fast, needs no induction and is also visible in late phases of viral replication. However, these experiments do not establish a causal relation between cAMP and Interferon.Work supported by the Swiss National Science Foundation, grants 3.1050 and 3.540.     

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.     

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).     

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

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.     

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.     

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.     

Memory corticalization triggered by REM sleep: mechanisms of cellular and systems consolidation

Once viewed as a passive physiological state, sleep is a heterogeneous and complex sequence of brain states with essential effects on synaptic plasticity and neuronal functioning. Rapid-eye-movement (REM) sleep has been shown to promote calcium-dependent plasticity in principal neurons of the cerebral cortex, both during memory consolidation in adults and during post-natal development. This article reviews the plasticity mechanisms triggered by REM sleep, with a focus on the emerging role of kinases and immediate-early genes for the progressive corticalization of hippocampus-dependent memories. The body of evidence suggests that memory corticalization triggered by REM sleep is a systemic phenomenon with cellular and molecular causes.