N. A. Sokolova

Effects of GSM-Frequency Electromagnetic Radiation on Some Physiological and Biochemical Parameters in Rats

Single exposure of white outbred rats to electromagnetic radiation with a frequency 905 MHz (GSM frequency) for 2 h increased anxiety, reduced locomotor, orientation, and exploration activities in females and orientation and exploration activities in males. Glucocorticoid levels and antioxidant system activity increased in both males and females. In addition to acute effects, delayed effects of radiation were observed in both males and females 1 day after the exposure. These results demonstrated signifi cant effect of GSM-range radiation on the behavior and activity of stress-realizing and stress-limiting systems of the body.

Effect of hypoxia during early organogenesis on cardiac activity and noradrenergic regulation in the postnatal period

Cardiac activity in rats during the postnatal period was studied in vitro and in vivo after exposure of rat pups to antenatal acute hypobaric hypoxia at the stage of organogenesis (day 9–10 of gestation). Cultured cardiomyocytes from rat pups exposed to antenatal hypoxia were characterized by increased rate of contractions and decreased reactivity to norepinephrine. Heart rate elevation, predominance of sympathetic influences on cardiac activity, and significant increase in norepinephrine concentration in the cerebral cortex were found in freely moving animals exposed to antenatal hypoxia. Our results indicate that hypoxia at the stage of organogenesis modulated cardiac activity during the postnatal period, which manifested at the level of effector structures in the heart and activity of regulatory systems.

Effects of single intranasal administration of obestatin fragments on the body weight and feeding and drinking behaviors.

336 Lately, there has been a growing body of evidence about endogenous peptide regulators of appetite. Par ticular attention among them is paid to obestatin, which is a derivative of preproghrelin and composed of 23 amino acid residues [1]. An anorexigenic effect of obestatin has been shown in a number of studies [1, 2]. However, the study of anorexigenic effects of obestatin fragments are of a special interest. According to some data, fragment 1–13 has the strongest anorexigenic effect [3]; according to others, fragment 11–23 has [4]. There has been almost no analysis of the effects of other fragments. Therefore, we have investigated the effects of different obestatin fragments on body weight changes and the intake of food and water given ad libi tum. For our study, we chose fragments 1–4, 5–10, and 10–15 as less studied ones and fragment 11–23 whose anorexigenic effect had been shown earlier.

Changes in feeding and drinking motivations and glucose content in male rats after single or chronic administration of obestatin or its fragment (1–4)

Obestatin is an endogenous regulator of appetite with anorexigenic action. In this study, we analyzed the effects of single and chronic intranasal administra� tions of obestatin or its fragment (1–4) at a dose of 300 nmol/kg on the glucose content of blood and food and water motivation under the conditions of depriva�

Effect of antenatal hypoxia on age-specific dynamics of ECG parameters and content of biogenic amines in the central nervous system.

We studied the effect of acute antenatal hypoxia during the stages of progestation and early organogenesis on some ECG parameters and level of biogenic amines in brain structures in rats. The effect of acute hypoxic exposure during the organogenesis period on the studied parameters was more pronounced than the effect of acute hypoxic exposure during the progestation period. The shift of the autonomic balance towards the sympathetic regulation of cardiac activity is linked with increased content of biogenic amines in the brain stem and cortical structures.

Effect of acute hypoxia in pregnant females on contractile activity of lymphatic vessels in the offspring.

Delayed consequences of acute hypoxia were studied in 60-day-old rat pups. The animals were exposed to acute hypobaric hypoxia on day 10 of embryogenesis. The offspring of intact females served as the control. Reactivity of mesenteric lymphatic vessels to norepinephrine was studied by vital microscopy. The frequency and duration of lymphatic vessel contractions in males significantly increased compared to the control. In females the duration of norepinephrine-induced lymphatic vessel contractions increased, while the frequency and amplitude of contractions and basal vascular tone did not differ from the control.

Effect of Anorexigenic Peptide Obestatin on Platelet Aggregation and Osmotic Resistance of Erythrocytes

We studied the effects of the anorexigenic peptide obestatin on the coagulation system and blood rheology (by the parameters of platelet aggregation and osmotic resistance of erythrocytes) in vitro and in vivo. Obestatin inhibited in vitro platelet aggregation in the entire dose range and reduced osmotic resistance of erythrocytes in all doses except 300 nmol/kg (obestatin in a dose of 300 nmol/kg had no effect on this parameter). Similar to the results of in vitro experiments, intranasal, intraperitoneal, and subcutaneous administration of obestatin in a dose of 300 nmol/kg inhibited platelet aggregation and had no effect on the osmotic resistance of erythrocytes.

Transgeneration Effects of Antenatal Acute Hypoxia during Early Organogenesis

We studied the effect of acute hypobaric hypoxia in early organogenesis on physiological and behavioral parameters of second-generation albino rats. Antenatal acute hypoxia was followed by physical and sexual retardation, increase in the mortality rate, and behavioral changes in second-generation animals (hypoactivity of males and females on day 22 of life and hyperactivity of males on day 57 of life). Second-generation animals exhibited no gender differences in body weight and horizontal and vertical locomotor activity.

Influence of intermittent normobaric hypoxia during early organogenesis on the development of white rats

The influence of antenatal intermittent normobaric hypoxia during early organogenesis (days 9–10 of intrauterine development) on the physical development, vegetative balance, and antioxidant defense system of 60-day-old rats was studied. Antenatal exposure to intermittent hypoxia resulted in the impaired physical development of all offspring during the early 15-day postnatal period and caused changes in the vegetative balance of heart regulation, which were differently directed in males and females. Moreover, females that survived antenatal hypoxia had a decreased superoxide dismutase activity in the brain, compared to that in the control rats.

Acute Hypoxia during Organogenesis Affects Cardiac Autonomic Balance in Pregnant Rats

Changes in ECG parameters were studied in pregnant rats exposed to acute hypobaric hypoxia during the period of organogenesis (gestation days 9 to 10). Rats with low, medium, and high tolerance to hypoxia exhibited pronounced autonomic nervous system imbalance, which become apparent as a loss of correlation between various parameters of ECG signals recorded at rest and during exposure to some stress factors existing under normal conditions.