Levels of selenium in the rat pineal gland: the effects of selenium supplementation

Levels of selenium (Se) were measured in the pineal glands of rats aged 4,5,8 and 12 months and the following corresponding levels of Se were determined: 1.058 nmol/gland, 0.63 nmol/gland, 0.58 nmol/gland and 0.43 nmol/gland. In the rat pineal glands obtained from rats which drank water containing Se coupled to brewers yeast (average daily intake of Se per animal was 0.5µg ) the following increased levels of Se were determined: 0.87 nmol/gland, 0.72 nmol/gland and 0.59 nmol/gland at the ages of 5,8 and 12 monthsrespectively. Since Se participates in the antioxidative defense of the mammalian organism, the increased levels of Se in the pineal glands of rats supplemented with Se in drinking water, may be of physiological benefit during ageing.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Calcium (Ca2+) content in the lower jaws of rats irradiated in the head region with X-rays

ct Irradiating the head region of 8-day-old rats with a dose of 8.64Gy of X-rays, at the age of 42 days, results in stunting of lower jaw growth as illustrated by measuring the length and height of the jaws. This irradiation dose also has as a consequence an increased content of Ca 2+ in the bone tissue of the lower jaw (270.36±27.97 mmol/kg bone tissue) when compared to the corresponding non-irradiated controls (188.58±19.26 mmol/kg bone tissue, p<0.05) and rats irradiated with a dose of 3.84Gy of X-rays (143.99±15.29 mmol/kg bone tissue, p<0.01).Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Effects of metal ions on plasma membrane Mg2+-ATPase in rat uterus and ovaries

The in vitro effects of cadmium and mercury were investigated on the Mg2+-ATPase activity of plasma membranes from the rat ovary and uterus. ATP hydrolyzing activities were significant and dose-dependent-inhibited in both plasma membrane preparations by both metals. According to the IC50 and apparent K-i, Cd2+ was most potent in the ovary, while Hg2+ was most potent in the uterus. In ovaries and uterus,Cd2+ inhibits competitively, while Hg2+ inhibits noncompetitively in both organs. The observed inhibition was a consequence of direct action of the chosen metal ions on the enzyme protein and by decreasing ATP hydrolysis, Hg2+ and Cd2+ may affect mammalian fertility.22nd International Biophysics Symposium, Oct 09-14, 2004, Belgrade, Serbi

Selective inhibition of brain Na,K-ATPase by drugs

The effect of drugs from the class of cardiac (methyldigoxin, verapamil, propranolol), antiepileptic ( carbamazepine), sedative (diazepam) and antihistaminic (promethazine) drugs on Na,K-ATPase activity of plasma membranes was studied in rat brain synaptosomes. Methyldigoxin in a concentration of 0.1 mmol/l inhibits enzyme activity by 80%. Verapamil, propranolol and promethazine in concentrations of 20, 20 and 2 mmol/l respectively, entirely inhibit the ATPase activity. Carbamazepine and diazepam in concentrations of 0.02-60 mmol/l have no effect on the activity of this enzyme. According to the drug concentrations that inhibit 50% of enzyme activity (IC50), the potency can be listed in the following order: methyldigoxin GT GT promethazine GT verapamil GT = propranolol. From the inhibition of commercially available purified Na, K-ATPase isolated from porcine cerebral cortex in the presence of chosen drugs, as well as from kinetic studies on synaptosomal plasma membranes, it may be concluded that the drugs inhibit enzyme activity, partly by acting directly on the enzyme proteins. Propranolol, verapamil and promethazine inhibitions acted in an uncompetitive manner. The results suggest that these three drugs may contribute to neurological dysfunctions and indicate the necessity to take into consideration the side effects of the investigated drugs during the treatment of various pathological conditions

Selective inhibition of brain Na,K-ATPase by drugs

The effect of drugs from the class of cardiac (methyldigoxin, verapamil, propranolol), antiepileptic ( carbamazepine), sedative (diazepam) and antihistaminic (promethazine) drugs on Na,K-ATPase activity of plasma membranes was studied in rat brain synaptosomes. Methyldigoxin in a concentration of 0.1 mmol/l inhibits enzyme activity by 80%. Verapamil, propranolol and promethazine in concentrations of 20, 20 and 2 mmol/l respectively, entirely inhibit the ATPase activity. Carbamazepine and diazepam in concentrations of 0.02-60 mmol/l have no effect on the activity of this enzyme. According to the drug concentrations that inhibit 50% of enzyme activity (IC50), the potency can be listed in the following order: methyldigoxin GT GT promethazine GT verapamil GT = propranolol. From the inhibition of commercially available purified Na, K-ATPase isolated from porcine cerebral cortex in the presence of chosen drugs, as well as from kinetic studies on synaptosomal plasma membranes, it may be concluded that the drugs inhibit enzyme activity, partly by acting directly on the enzyme proteins. Propranolol, verapamil and promethazine inhibitions acted in an uncompetitive manner. The results suggest that these three drugs may contribute to neurological dysfunctions and indicate the necessity to take into consideration the side effects of the investigated drugs during the treatment of various pathological conditions

Early effects of ionizing radiation on rat brain NTPDase activity

IUBMB 50th Anniversary Symposium, Jul 02-07, 2005, Budapest, Hungar

Inhibition of rat brain ecto-ATPase activity by various drugs

The in vitro effect of digoxin, verapamil, propranolol, carbamazepine, diazepam and promethazine were investigated on the ecto-ATPase activity of synaptosomal plasma membranes from the rat brain. ATP hydrolyzing activities of the enzyme were not affected by digoxin while the use of all other drugs resulted in significant and dose-dependent ihibition in ATP hydrolysis. According to values Of IC50 and K-iapp, the order of inhibitory potency of the drugs applied was: diazepam GT promethazine GT verapamil GT propranolol GT GT carbamazepine. Kinetic analysis of the nature of the ATPase inhibition revealed that it resulted from a direct action of drugs on the enzyme protein. The aim of the present study was to determine the potential neuromodulatory side effects of the drugs investigated. The results achieved indicated that all investigated drugs, except digoxin, may modulate neuronal activities via the purinergic receptors P2 by increasing extracellular concentrations of ATP as a consequence of inhibition of the ecto-ATPase activity. Our findings indicate that it may be useful to take into consideration the possible side effects of the investigated drugs, when they are used in treatment of different pathologies, particularly in the treatment of epilepsy by carbamazepine and diazepam