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V M Koval'zon

Publications and source records attributed to V M Koval'zon.

At least 19 recordsLinked to original sources
PubMed2005

Actions of pulsed ultra-broadband electromagnetic irradiation on the EEG and sleep in laboratory animals.

Irradiation of animals with ultrashort impulses of ultra-broadband magnetic irradiation with an impulse repetition frequency of 6 Hz for 1 h induced changes in the spectral composition of cerebral cortex electrical activity in rats, measured over the 5 min immediately after irradiation, as compared with controls. In particular, there was suppression of frequencies close to the impulse sequence frequency, along with a decrease in interhemisphere coherence. Continuous recording of polygrams for 22 h from rabbits after irradiation revealed a "delayed" effect--a significant increase in paradoxical sleep, starting 16 h after the end of irradiation and persisting to the end of the recording period. It is suggested that irradiation has a direct action both on the mechanisms of generation of the theta rhythm (septohippocampal) and on the system controlling circadian rhythms (the suprachiasmatic nucleus-epiphysis system).

Acoustic Stimulation↗
PubMed1994

[Muramyl peptides and sleep].

Effects of muramyl peptides from bacterial cell walls (MDP and GMDP), their fragments, steric isomers and structural analogues were studied on sleep in rabbits. An increase in the SWS, decrease in PS, rise in body temperature were found following minimal doses, whereas pathological responses in the EEG and sleep as well as pyrogenic effects occurred after higher doses. The GMDP analogues affected sleep weakly, and isomers and fragments were inactive. Possible role of muramyl peptides in normal and pathological regulation of sleep is discussed.

Animals↗
PubMed1986

[Active analog of the inactive "sleep peptide"].

Delta Sleep-Inducing Peptide (DSIP) was not previously found to possess hypnogenic properties. Its analogue (D-TrpI)DSIP was more stable against aminopeptidases. Its intracerebrovascular administration in doses of 0.7, 7 and 70 micrograms/kg body weight induced a significant increase in slow wave sleep (by 40%; p less than 0.01, U-test) and rectal temperature elevation (by 0.9 degrees C; p less than 0.01) within the following 3 day-light hours, as compared to the control rabbits treated with physiologic saline. Intravenous injections of the DSIP analogue increased slow wave sleep by 25% in a narrow dose range (30-70 micrograms/kg).

Animals↗
PubMed1978

[Deprivation of "rapid" sleep by stimulation of the reticular formation of rats].

Rats were repeatedly arused from REM sleep by the stimulation via implanted midbrain reticular electrodes. The 4-day seprivation reduced REM sleep by 50% whereas the slow-wave sleep was only reduced by 10%. There was no evidence of a disruption in the animal behaviour during the deprivation and no changes of emotional responsiveness in the "open-field" at the end of the deprivation. REM deprivation produced a slight but statistically significant (P = 0.025) adrenal weightlos. Thymus weight was unchanged and no stomach ulcers developed. Therefore the REM deprivation as such did not appear to produce stress in rats.

Adrenal Glands↗
PubMedDate not supplied

[Hypnogenic properties of DSIP peptide analogs: structural-functional relationship].

The sleep-inducing activity of Delta Sleep-Inducing Peptide (DSIP) and its 13 synthetic analogs has been studied on rabbits with preliminary implanted electrodes. The peptides were injected into the lateral ventricle of cerebrum. Polygraphic computer monitoring of sleep-wake states was carried out at daytime for 7-12 h. DSIP and most analogs had no statistically significant effect on sleep compared to the control administration of saline to the same animals. [NMeAla2]DSIP and [Pro2]DSIP had a pronounced sleep-inducing effect and reliably increased the proportion of slow-wave sleep by 10-15% on average compared to the control. Several other analogs had a week sleep-inducing effect, increasing the proportion of slow-wave sleep during specific recording time only. [beta-Ala2]DSIP significantly suppressed sleep. In addition, this analog, as well as parent DSIP and four proline-containing nonapeptides, slightly increased the body temperature. The revealed differences may be due to both conformation properties and proteolytic resistance of the studied molecules, and it may reflect their indirect involvement in the control sleep-wake hormonal processes.

Animals↗
PubMedDate not supplied

[The hypnogenic effects of delta sleep-inducing peptide (DSIP) analogs: a comparative study in rabbits and rats].

Hypnogenic effects of 3 DSIP analogs with a higher stability against aminopeptidase activity have been studied in rabbits and rats using intraventricular administration (injections and infusions). An analog (D-Ala-2) DSIP augmented slow wave and paradoxical sleep within the 5th, 8th and 11th hours of the recording period. An analog (D-Val-2) DSIP made the same within the 8th and 10th hours, and hexapeptide (D-Ala-2) DSIP (1-6) increased sleep during the 1st, 3rd, and 5th hours. Both nonapeptides augmented sleep in rabbits as well as in rats, though hexapeptide produced this effect in rabbits only, that might be related to some difference in distribution and colocalization of endogenous DSIP-like peptide in the pituitary of two rodent species. It may be suggested that hypnogenic activity of DSIP analogs is determined by the structure of administrated molecule, being mediated by such hormones as GRF and CLIP.

Aminopeptidases↗
PubMedDate not supplied

[Effect of deprivation of the "rapid" phase of sleep on self stimulation of the hypothalamus and septum in white rats].

26 rats with bipolar electrodes in lateral hypothalamic and septal areas were learned to press the bar for electrical stimulation of the brain (monopolar square pulses, 0.1 msec, 100 cps, train length 250 msec). After stabilization of self-stimulation (SS) responses, the animals were deprived of rapid eye movement sleep (REM) for up to 4 days by confinement to a small platform surrounded by water. The rats were allowed to SS for 40 min per day during and after REM deprivation up to 1 month. It was found that REM deprivation strongly increased hypothalamic SS rates but failed to change SS thresholds. As to the septal SS, its rate either increased, with threshold unchanged or lowered (1st type), or remained steady (2nd type), or decreased, with threshold unchanged or risen. In most cases the deprivation led to alteration in the shape of SS rate/intensity curve, which remained during the whole experimental period (1 month).

Animals↗
PubMedDate not supplied

[Peptidergic modulation of sleep: a comparative study of analogs of the peptide DSIP].

Effects of intracerebroventricular administration of 3 DSIP analogues with higher stability against proteolysis, on subsequent sleep were studied in rabbits and rats previously implanted with electrodes and cannulas. Significant increase of total sleep time (mainly due to slow wave sleep) after administration of the peptides (D-Trp1) DSIP and (D-Tyr1) DSIP as compared with the control injections to the same animals was found during the first 3-5 hours in rabbits and 12 hours in rats. Shortened analogue (D-Trp1) DSIP1-6 had no effect on rabbit sleep and significantly reduced slow wave sleep in rats during the first 3 hours. It is concluded that some DSIP-like peptides which are more stable against aminopeptidases, can modulate rodent sleep.

Animals↗