DEPARTMENT OF BIOCHEMISTRY

Research Group of Prof. Mihajlo B. Spasić

Brief description of current research for Ana Mijušković and Prof. Mihajlo B. Spasić

The fact the endogenous H₂S is produced in specific mammals' tissues suggests its possible physiological functions. Having regarded to the pKa values, in biological systems at physiological pH of 7.4 and a temperature of 37°C, the H₂S will be more than 80% as HS^-. There is a little attempt in literature to identify the species that are the dominant carriers of physiological effects of H₂S. Using CH₃SH (methanethiol), which is under physiological conditions only in molecular form, and comparing its effects with the effects of H₂S donor - Na₂S, in the paper: "Comparison of the effects of methanethiol and sodium sulphide on uterine contractile activity" by Ana Mijušković, Zorana Oreščanin-Dušić, Aleksandra Nikolić-Kokić, Marija Slavić, Mihajlo B. Spasić, Ivan Spasojević and Duško Blagojević, which will be published in the Pharmacological Reports (2014), the authors conclude that CH₃SH may have a constructive role in the control of muscle function and metabolism. Observed differences between CH₃SH and H₂S/HS^- could be attributed to specific effects of HS^- associated with its negative charge. Effects of sodium sulfide further examine in the system of contraction (spontaneous and Ca²⁺-induced) of the uterus, where we found Na2S caused a dose-dependent relaxation of contraction (spontaneous and Ca²⁺-induced) of the uterus that is not cAMP, cGMP, Ca_v, or K_ATP-dependent, but mediated by Cl^- channels. The differences between the effects of Na₂S on spontaneous and Ca²⁺-induced contraction we examine in more detail by the application of KCl induced contraction and specific inhibitors.

Brief description of current research for assistant professor Dr. Milan Nikolić

Starting from the preliminary and published results on the influence of selected second-generation antipsychotics on human erythrocytes and protective antioxidant system, the comprehensive in vivo research of pharmacological effects of clozapine, sertindole and ziprasidone are in progress, using male Wistar rats as a model system. Systemic effects of C- phycocyanin, a major protein of cyanobacteria Spirulina sp. (genus Arthrospira), and its chromophore phycocyanobilin, are investigated by multidisciplinary approach. The third line of research work involves supplementation of previously published findings on hemoglobin-cholesterol adduct, as a new form of cholesterol in the human body: the hypothesis of erythrocytes as a buffer system for (potentially harmful) cholesterol surpluses in the circulation of healthy individuals is tested by examining the content and distribution of cholesterol in the blood of subjects with defined pathophysiological conditions. Ongoing research also covers the impact and contribution of cation-π and anion-π interactions on the stability of proteins and protein aggregates.