9th multidisciplinary international

Conference of Biological Psychiatry

«Stress and Behavior»

Proceedings of the 9th International Multidisciplinary Conference «Stress and behavior» Saint-Petersburg, Russia, 16-19 May 2005 Editor: Allan V. Kalueff, PhD



K.A. Hudik, K.V. Lapshina, S.Yu. Eram, T.N. Mankovskaya

Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg, Russia, Institute of Physiology NAS, Minsk, Belarus

The superfamily of heat shock proteins, particularly the HSP70 family, is known as the universal protective system of the organism. Over the last few years, studies in vitro indicate that exogenous HSP70 may possess cytoprotective properties (Margulis, Guzhova, 2000). Our laboratory of comparative termophysiology revealed that the central microinjections of HSP70 bibetated from lipopolysaccaride (LPS) elicited a marked increase in the total time of non-rapid-eye-movement sleep (NREMS) due to lengthening its episodes (Pastukhov et al., 2004). The analysis of somnogenic and somatovisceral effects of HSP70 allowed us to suggest the hypothesis about the enhancement of neuroprotective function of NREMS due to injection of HSP7. It is unclear whether the NREMS intensity changes following injection of HSP7. Trachsel et al. (1986) and other authors described increased power density in delta-diapason after prolonged wakefulness or during the post-stress period. This criterion is traditional for assessment of NREMS intensity. Earlier, investigations have shown that the effect of HSP70 containing the LPS on physiological characteristics is dose-dependent (Pastukhov et al., 2003). The goal of this investigation is to study effect of a relatively small dose of HSP70 preparation isolated from LPS on spectral characteristics of NREMS before and after the stress. Investigations were carried out in freely moving pigeons (Columba livia) and rats. The total sleep deprivation in pigeons was evoked by a tactile and sound stimulation during 5 h (4 h light: 1h dark). Exogenous HSP70 preparation was injected into the III brain ventricle after the end of stress as well as without stress. The preparations were obtained at the Institute of Cytology RAS (Guzhova et al., 1998). In the control, saline and phosphate buffer in the same volume as the HSP70 were injected. Continuous record (24 h or more) of electrophysiological parameters (contractile muscular activity CMA, heart rate, brain temperature Tb, tail temperature (rats) and temperature of unfeathered leg part (pigeon)) was carried out by computer system (SASR). The EEG power spectra was normed respectively to the power density in the frequency range from 1 to 30, and was analysed with special computer programs. The experiments in rats have shown that the power density in the frequency range from 0.75 to 2 Hz was predominant during the NREMS in the control and after injection of HSP7. Percent correlation between the delta-range (0.75—4 Hz) and the frequency range (1—30 Hz) did not differ from the control level. The association between the power density from 0.75 to 4 Hz, changes in the total time of NREMS, duration of episodes and brain temperature was not found. The experiments in pigeons have revealed that injection of HSP70 increased the NREMS total time and the duration of its episodes without an increase in power spectrum. The sleep deprivation in pigeons induced an increase in power density during the rebound of NREMS. The same effect was observed after injection of HSP70 at the end of sleep deprivation. It is to mentioned that the increase of power spectrum after sleep deprivation and injection of HSP70 immediately after the end of stress led to the similar result. In experiments in pigeons, the association between the delta sleep power density (0.75—4 Hz), changes in the total time of NREMS, duration of NREMS episodes and brain temperature was not found as well as in experiments in rats. Central microinjections of HSP70, isolated from LPS, induced a marked increase in the total time of NREMS and duration of episodes and did not change its power density in the frequency range 0.75—4 Hz under moderate stress and non-stress conditions in rats and pigeons. The study was supported by RFRF (grant 03-03-33034).

Psychopharmacol. Biol. Narcol. 2005. Vol. 5, N 2. P. 894-895 Psyhopharmacology & biological narcology

ISSN 1606-8181