PubMed Health⌕ Search

Biomedical subjects

R I Kovalenko

Publications and source records attributed to R I Kovalenko.

At least 19 recordsLinked to original sources
PubMed2003

The effects of epiphyseal peptides on the release of immunoglobulins in Peyer's patches in rats in vitro.

The effects of epiphyseal peptides (1 microg/ml) on the release of immunoglobulins into the incubation medium by isolated Peyer's patches from non-immunized mice and mice immunized orally against ovalbumin were studied during 40-min incubations. The possibility that epiphyseal peptides act on adrenoreceptors of cells in secondary lymphoid organs in the small intestine was assessed using alpha- and beta-adrenoreceptor blockers, i.e., phentolamine HCl (0.02 mg/ml) and anaprilin (0.06 mg/ml) respectively. Basal levels of secretory activity in control Peyer's patches from immunized rats were 2.4 times (p < 0.01) greater than for the lymphoid organs of non-immunized animals. The effects of epiphyseal peptides on the secretory activity of antibody-forming cells depended on the functional state of Peyer's patches. Application of epiphyseal peptides led to a 35% increase (p < 0.05) in the release of immunoglobulins from Peyer's patches in non-immunized rats and a 25% decrease (p < 0.05) in the release of antibody into the incubation medium from the lymphoid organs of immunized animals. These data lead to the suggestion that the activatory effect of epiphyseal peptides on antibody-forming cells in Peyer's patches from non-immunized animals is associated with alpha-adrenoceptors, while their inhibitory action on immunoglobulin release by the small intestine lymphoid organs from immunized animals is not mediated via adrenoceptors.

Adrenergic Agonists↗
PubMed2003

[Pineal peptides in the regulation of milk-ejection reflex in lactating rats].

The effects of pineal peptides (mol. mass 1-4 kDa) intranasal infusions on some parameters of milk-ejection reflex were investigated. Peptides were extracted from dairy-cattle pineal glands. Pineal peptides increase body weight, levels of water intake, plasma prolactin concentration and milk yield in rats when infusing daily in dose 1 microgram/kg from the third day of lactation. On 9th and 12th days of lactation during 1-hour nursing seance the significantly greater number of reflective milk ejections were found. When 1 hour before the peptides infusion rats were intraperitoneally injected by rabbit antiserum to oxytocin (200 microliters at dilution of 1:20) the effects of pineal peptides were significantly less expressive or were absent at all. Using enzymimmunoassay it was demonstrated that there were greater increasing of oxytocin content in pineal gland in suckling-induced oxytocin release from neurohypophysial system in the chronic pineal peptides-treated female rats compared with control. This effect was absent when rats were injected by oxytocin antibodies. These data suggest that pineal peptides can participate in forming of reflect oxytocin release pattern. This pattern is initiated by suckling and is limited by oxytocin content in blood.

Administration, Intranasal↗
PubMed2003

[Effect of pineal peptides on the adrenal gland cortex glucocorticoid function and behavior in rats orally immunized with ovalbumin].

The influence of intraperitoneal injections of pineal peptides (5 mg/100 g of body mass during first five days of three weeks' oral immunization by ovalbumin) on the rats' behavior in the "open field" tests and on the blood corticosterone level, was investigated. It was found out that rats' oral immunization resulted in increasing of secretion activity of Peyer's patches antibody-producing cells, in decreasing of blood leukocyte cytokine-producing activity, in depression of the searching behavior and locomotor activity and in a significant (p < 0.05) lowering of the blood corticosterone level after 15 minutes in the "open field" tests. The pineal peptide injections caused an intensification of humoral immune response, a more obvious suppression of locomotor activity and searching behavior, and a significant decrease of the corticosterone level compared to the animals intraperitoneally injected by physiological solution. These data indicate that immuno-stimulative effect of pineal peptides combines with their ability to decrease glucocorticoid hormone secretion during stress-reaction.

Adjuvants, Immunologic↗
PubMed2003

[Mechanisms of human adaptation to hypoxia].

The effects of adaptation to cold-and-hypoxic exposure on the cardiovascular system, lipid peroxidation and concentrations of adaptogenesis involved hormones were studied in male students. The two weeks cold- and hypoxic training was shown to be accompanied by a significant increase of apnea duration, reduced velocity of bradycardia development and a more rapid ECG post-cold and- hypoxic exposure normalization, as well as by inhibition of activation of adrenal cortex and thyroid gland after stress of different nature. The changes of the character of influences between the indices under study, were demonstrated. The correlation analysis showed an increase of the human's adaptive potential and a decrease of its dependence on the adrenal cortex hormones.

Adaptation, Physiological↗
PubMed2002

[The influence of pineal peptides on in vitro immunoglobulin secretion by Peyer's patches in rats].

The influence of the pineal peptides (1 mcg/ml) on immunoglobulin secretion by rat's Peyer's patches isolated from nonimmunized rats and from orally immunized by ovalbumin during 40 min incubation, was investigated. Using alpha- and beta-adrenoblockers--phentolamine hydrochloride (0.02 mg/ml) and anaprilin (0.6 mg/ml), respectively--the possibility of pineal peptides' effect on the gut secondary lymphoid organ' adrenoreceptors, was evaluated. Basic levels of immunized rats' control Peyer's patches secretory activity were 2.4--fold (p < 0.01) higher than those of non-immunized rats. The effect of pineal peptides on antibody-producing cells' secretory activity depended on Peyer's patches' functional condition. Application of pineal peptides led to a 35% (p < 0.05) increasing of immunoglobulin secretion by non-immunized rat Peyer's patches and to a 25% (p < 0.05) decreasing of antibody production by immunized rats lymphoid organs. These data suggest that the pineal peptides activation influence on Peyer's patches antibody-producing cells of nonimmunized rats connected with alpha-adrenoreceptors, and inhibiting action of these peptides on immunized rats lymphoid organs immunoglobulin secretion are not mediated through adrenoreceptors.

Adrenergic Antagonists↗
PubMed2001

[Activation of the antioxidant system as a factor in increasing the body resistance during combined adaptation].

In semi-aquatic mammals (minks and muskrats) significant changes were found to occur in the leukocyte formula during adaptation to hypoxia, as compared with non-adapted rats and mice, although no increase in lipid peroxidation was found in any of their organs. This latter finding seems to be due to simultaneously enhanced activities of superoxide dismutase and catalase. In humans under professional stress, treatment with combined technology of adaptation: cold-and-hypoxic exposure, yields a positive therapeutic result accompanied by a decrease in lipid peroxidation and increase in superoxide dismutase and catalase activities in the blood. The data obtained suggest that the strategy of formation of protection against hypoxia and toxic free radical oxidation is common for the animals and humans.

Adaptation, Physiological↗
PubMed2000

[Pinealocyte functioning in stress during daytime in rats].

Several types of unit activity were detected in the rat pineal gland during a 48-hour water and food deprivation. The unit activity rate in stress was higher by 4-6 times than in intact rats (due to an increase in the "fast" cells number and switching of some cells from regular to a burst type of activity). Electrical stimulation of olfactory epithelium decreased the unit activity rate in the most active pinealocytes. The daytime increase in the pineal electrical activity reflects an intensification of secretion of the protein/peptide substances and, probably, serotonin but not the melatonin. Blocking exocytosis with colchicin revealed a close relation of the pinealocytes secretion with their electrical activity. Existence of central (olfactory in particular) mechanisms limiting the pineal activation, was shown.

Animals↗
PubMed1995

[The lateralization effect of oxytocin on the functional activity of paired visceral organs in rats].

Following unilateral intranasal oxytocin administration, asymmetric alterations in some functional parameters of the adrenal glands, testis, lungs and heart, occurred. The lateralization of alterations was dependent on the side of oxytocin injection and the side of paired organ arrevgenent. Possible pathways of intranasal oxytocin administration effects on visceral organs as well as causes of their asymmetry, are discussed.

Administration, Intranasal↗
PubMed1994

[The effect of the intraventricular administration of oxytocin on the functional activity of the epiphysis, adrenals and gonads and on the behavior of rats].

Intraventricular administration of oxytocin (OT) facilitated horizontal locomotion and inhibited their decrease in rats. OT also increased the number of face grooming responses but did not affect the genital grooming. The OT seems to suppress the pineal gland activity, whereas the plasma concentration of testosterone did not change and the corticosterone concentration increased. The OT seems to exert a complex effect on the nervous and endocrine systems.

Adrenal Glands↗
PubMed1994

[Cardiovascular system reactions and bioenergy metabolism in relation to adaptation to apnea].

Responses of the cardio-vascular system and bioenergetic metabolism were studied in the heart tissue in apnoea in naturally adapted to diving musk-rats and unadapted rats and mice. A sharp bradycardia was shown to develop in former animals in arresting a breathing as well an increase in the neutrophils contents in the blood. The data obtained suggest that release of the necessary oxygen and antiradical defence functions can be related to the catalase activity.

Adaptation, Physiological↗
PubMed1994

[The neuroendocrine aspects of the participation of the epiphysis in the regulation of lactation].

Pinealectomy was shown to suppress the milk ejection reflex and increase the luteinizing hormone secretion in lactating rats. Suckling caused the same type changes of prolactin though at a lower level, in these rats. The data obtained suggest that the pineal gland together with the oxytocinergic system are involved in complex mechanisms of neurohumoral regulation of the lactogenic and gonadotropic hormones secretion during lactation.

Animals↗
PubMed1987

[Ultrastructural changes in the pinealocytes of the rat in the late period after hypophysectomy].

Changes in the ultrastructure of epiphyseal pinealocytes were examined 3 weeks after hypophysectomy in infantile male rats in order to study functional relations of pineal gland with the hypothalamo-hypophyseal system. In hypophysectomized animals the functional activity of pineal secretory cells was found to decrease. Besides, the symptoms of suppression of biosynthetic processes and energy metabolism, as well as lipid infiltration and degradation of intercellular contacts, were observed.

Animals↗