Effect of panangin on activity of messengers systems in hypertrophied rat myocardium.

The balance between the two major second messenger systems in hypertrophied myocardium was studied in rats receiving panangin for 16 days. Panangin producing stimulating and polarizing effects on cardiomyocyte membrane improved electrophysiological characteristics of hypertrophied myocardium (electrical stability, duration of supernormal excitability period, and action potential), activated the phosphoinositide exchange, and inhibited the adenylate cyclase system. The panangin-induced change in membrane potentials was accompanied by a pronounced inositol response, i.e. a decrease in the content of membrane polyphosphoinositides (phosphatidylinositol-4-phosphate and phosphatidylinositol-4,5-biphosphate) in the brain. It was concluded that function of ion channels depends on activity of phosphoinositide- and adenylate cyclase second messengers systems.

The influence of rapid potassium administration on hemodynamics and endogenous catecholamine production during extracorporeal circulation.

In a prospective randomized double-blind study, the peripheral vascular effects of potassium chloride (KCl) and potassium-magnesium-aspartate (KMA) were compared. Twenty patients undergoing coronary artery bypass graft surgery received either 12 mmol of KCl (n = 10) or 12 mmol of KMA (n = 10) into the oxygenator of the heart-lung machine during extracorporeal circulation (ECC). The most striking difference between these two solutions was vasoconstriction following KCl administration and vasodilation after KMA injection. In the KMA group, decreases of perfusion pressure (MAP) and systemic vascular resistance (SVR), as well as changes in the oxygenator volume (dV), were significant (P less than 0.01) between the first and the fifth minutes. Maximal changes of MAP, from 72 +/- 13 to 59 +/- 12 mmHg (mean +/- SD), and SVR were recorded in the first and second minutes. Oxygenator volume changes reached their maximum (285 +/- 163 mL) in the tenth minute. In the KCl group, maximal increases in MAP, from 70 +/- 16 to 81 +/- 20 mmHg (mean +/- SD), and SVR were found in the fourth minute. Maximal changes in dV (300 +/- 315 mL) were measured in the tenth minute. Plasma epinephrine levels, which were already elevated during ECC, showed further increases in all cases in the KCl group and in most of the cases in the KMA group. The change in plasma epinephrine concentration following KCl injection was significant (P less than 0.01). No characteristic change in plasma norepinephrine was found in either of the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Comparative study on myocardial damage in irradiated for a long time and nonirradiated rats after administration of FCOL]. / Vergleichende Studie über Myokardschädigungen nach Applikation von FCOL an langzeitbestrahlten und unbestrahlten Ratten.

The trials were made to assess the effect of FCOL (9-alpha-fluorocortisol + Na2HPO4) and the effect of K and Mg asparaginates and their mixtures on the modifications of Ca2+, Na+, and K+ ions and of the K/Na ratio in the myocardium of rats not irradiated or submitted to permanent whole-body irradiation (gamma irradiation with 0.57 Gy per day during 25 days, total accumulated dose 14.25 Gy; the trials were performed 25 days after the irradiation). The totality of reversible and irreversible functional modifications of the myocardium, expressed by the quantitative assessment of the K/Na ratio and the concentration of Ca2+ ions, was evaluated in order to determine the cardiotoxicity or cardioprotection. It was demonstrated that irradiation alone causes a slight irreversible modification in the myocardium which is not found in non-irradiated rats. FCOL itself increases the rate of Ca2+ and Na+ ions in irradiated and non-irradiated rats, but does not influence the quantity of K+ ions. Severe irreversible myocardial damages are caused by FCOL, but these damages are considerably lower in irradiated rats. Neither in irradiated nor in non-irradiated rats, the isomers of Mg asparaginate show any protective action against the cardiotoxic effect of FCOL. The isomers of K asparaginate, also combined with Mg asparaginates, as well as the preparation Inzolen exert a demonstrable protective effect against myocardial ion modifications following to application of FCOL. The protection is more efficient in irradiated rats.

Effect of K and Mg salts of aspartic acid on haemopoiesis and recovery from radiation damage in mice.

Male mice of a non-inbred strain "H" were used to verify the effect of a 10-day peroral administration of K and Mg aspartates on haemopoietic functions. The salts were proved to stimulate the proliferation and differentiation processes in the thymus, bone marrow and spleen tissues. Mice exposed to a single whole-body X-irradiation after pretreatment with K, Mg aspartate exhibited a more conspicuous postirradiation regeneration of haemopoietic organs and an increased postirradiation survival. The results suggest the possibility of using K, Mg aspartate for radioprotective purposes.

The effect of magnesiumaspartate on preservation of the rat liver.

1. Isolated rat livers reperfused with an oxygenated isotonic Mg-aspartate or saline solution and stored 1 h at 36 degrees C, 4 h at 22 degrees C or 12 h at 6 degrees C were reperfused at 37 degrees C 150 min with a Krebs-Henseleit solution containing bovine albumin and erthrocytes gased with a 95% O2-5% CO2 gas mixture. 2. Light- and electronmicroscopic studies revealed minor changes after storage, whereas in the reperfused livers a focal distribution of well preserved and disintegrated hepatocytes was observed. 3. During storage the sum of adenine nucleotides in general decreased markedly paralleled by a significant rise of the lactate/pyruvate and hydroxybutyrate/acetoacetate ratios and pronounced breakdown of glycogen. Oxidative phosphorylation was resumed upon reperfusion resulting in de novo synthesis of ATP and ADP. The lactatelpyruvate and hydroxybutyrate/acetoacetate ratios normalized, whereas a resynthesis of glycogen was missing. 4. No conclusive evidence of a protective Mg-effect as observed in induced cardiac arrest has been obtained, probably due to structural and metabolic differences between the two organs and microcirculatory disorders as has been demonstrated by measurements of oxygen uptake using the multiwire electrode.