E. N. Goncharenko

Elucidation and Characteristics of Non-opioid β-Endorphin Receptors in Rat Adrenal Cortex

Abstractβ-Endorphin-like decapeptide immunorphin (SLTCLVKGFY), a selective agonist of non-opioid β-endorphin receptor, was labeled with tritium to specific activity of 24 Ci/mmol. It was used for the detection and characterization of nonopioid β-endorphin receptors on rat adrenal cortex membranes (Kd1 = 39.6 ± 2.0 nM, Bmax1 = 40.7 ± 2.3 pmol/mg protein; Kd2 = 0.25 ± 0.01 μM, Bmax2 = 187.8 ± 9.4 pmol/mg protein). β-Endorphin was found to inhibit the [3H]immunorphin specific binding to membranes (Ki = 70.0 ± 9.2 nM); naloxone, [Met5]enkephalin, and α- and γ-endorphins tested in parallel were inactive. Immunorphin at concentrations of 10–9-10–6 M was found to inhibit the adenylate cyclase activity in adrenocortical membranes, while intramuscular injection of immunorphin at doses of 10-100 μg/kg was found to reduce the secretion of 11-oxycorticosteroids from the adrenals to the bloodstream.

β-Endorphin-like peptide SLTCLVKGFY reduces the production of 11-oxycorticosteroids by rat adrenal cortex through nonopioid β-endorphin receptors

Abstract β-Endorphin-like peptide immunorphin (SLTCLVKGFY), a selective agonist of nonopioid β-endorphin receptor, was labeled with tritium to specific activity of 24xa0Ci/mmol. It was used for the detection and characterization of nonopioid β-endorphin receptors on rat adrenal cortex membranes ( K d =31.6±0.2xa0nM, B max =37.4±2.2xa0pmol/mg protein). Immunorphin at concentrations of 10 −9 to 10 −6 xa0M was found to inhibit the adenylate cyclase activity in adrenal cortex membranes, while intramuscular injection of immunorphin at doses of 10–100xa0μg/kg was found to reduce the secretion of 11-oxycorticosteroids from the adrenals to the bloodstream.

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.

Synthetic peptide immunocortin stimulates the production of 11-oxycorticosteroides by rat adrenal cortex through ACTH receptors

Adrenocorticotropic hormone (ACTH)-like peptide immunocortin (IMC) VKKPGSSVKV, corresponding to the amino acid sequence 11-20 of the variable part of human immunoglobulin G (IgG) 1 heavy chain, at concentrations of 10(-9)-10(-6) I was found to increase the adenylate cyclase activity in adrenal cortex membranes, while intramuscular injection of immunocortin at doses of 10-100 microg/kg was found to stimulate the secretion of 11-oxycorticosteroids (CS) from the adrenals to the bloodstream. Immunocortin was labeled with tritium to specific activity of 22 Ci/mmol. Receptor binding studies revealed that [(3)H]immunocortin ([(3)H]IMC) bound with high affinity and specificity to ACTH receptors on rat adrenal cortex membranes (K(d)=2.1+/-0.2 nM, B(max)=1.1+/-0.1 pmol/mg protein).

Effect of middle-wave ultraviolet irradiation and red light on degranulation of peritoneal mast cell in rats.

Middle-wave UV-irradiation inhibits liberator-induced histamine release from mast cells. Red light stimulated liberator-induced degranulation of mast cell. The existence of a membrane-dependent system activated by long-wave (red) light in mammalian cells is discussed.

Protective effect of carnosine in hyperthermia

Under the conditions of hyperthermia, carnosine (β-alanine-l-histidine) normalizes tissue contents of lipid peroxidation products, cytochrome P-450, serotonin, and histamine in rats and increases their survival after extreme hyperthermia.

Effects of Cold Stress and Epinephrine on Degranulation of Peritoneal Mast Cells in Rats

We studied the effects of histamine liberators calcium ionophore A23187 and substance 48/80 on mast cells during cold stress and epinephrine load. Under the effect of both stress factors, ionophore A23187-induced histamine release from mast cells underwent more pronounced changes than that stimulated by substance 48/80. Cold stress and epinephrine load produce different changes in functional activity of Ca2+ channels in mast cell membranes.

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.

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.

Effect of ultraviolet B irradiation on immobilization stress-induced changes in the protective systems of C57Bl/6 mice.

We studied the effect of ultraviolet B irradiation on superoxide dismutase activity, ceruloplasmin level in the plasma, and steroid hormone concentration in the adrenal glands of C57Bl/6 mice subjected to immobilization stress. Ultraviolet B irradiation did not abolish the increase in superoxide dismutase activity, but decreased ceruloplasmin level in the plasma and corticosteroid concentration in the adrenal glands of mice exposed to immobilization stress.