Farmakologija - eksperimentalna (Slovene)

Equinatoxin (EqT-II) contracted coronary arteries in isolated hearts of guinea-pigs, rats and pigs. This effect depended on Ca2+ and Mg2+ concentration. Ca2+ antagonist decreased these effects and the CaCl2-induced contraction of isolated porcine coronary and human tibial artery. The prevailing of L-type over T-type Ca2+ channels in the wall of both arteries was shown. On the isolated porcine coronary artery we proved the involvement of Ca2+ channels in the effects of the whole bee-venom. In the postischaemic damage in rat heart T-type Ca2+ channels are more important than L-type. The preventive role of Ca2+ antagonist has been shown in isolated hearts of guinea-pigs with acute renal failure. The analytical method of non-linear dynamics confirmed that chaotic measures could be used in classifying long term continuous arrhythmias. The test of non-linearity showed that some types of ventricular fibrillation had characteristics of non-linear, and others of stochastic dynamics. The planparallel method was used to determine the thermal conductivity of different parts of porcine heart tissue at different temperatures. EqT-II was found to be an efficient histamine releaser from mast cells, isolated from the rat peritoneal cavity eluent. In the experiments (on cats and rats, in vivo and in vitro), amitriptiline diminished the rise of free exogenous and/or released histamine in plasma, the finding that complemented our previous results. In the study of the effects of histamine antagonists on histamine kinetics in the cat, fexofenadin most efficiently changed histamine kinetics. The parameters of concentration-response relationship for histamine and pA2 value for famotidine on the isolated guinea pig atrium and isolated part of guinea pig stomach were significantly different; the result was explained by nonequilibrium conditions in the stomach preparation. In the guinea pig isolated trachea, depletion of mast cell histamine stores diminished the contractile effect of muscarinic agonist, indicating the involvement of endogenous histamine in the effect, elicited by muscarinic stimulation. The experimental results were shown in international congresses in Budapest, in Lyon and in Gozd Martuljek (Life Sciences). Our group collaborates with research groups in Innsbruck, Graz and Stockholm.