Toxicology of thallium

Mitochondrial Oxidative Stress Is the General Reason for Apoptosis Induced by Different-Valence Heavy Metals in Cells and Mitochondria

“…We have shown that excess Tl + ions are removed from mitochondria when using a K + /H + exchanger, which is followed by the pumping out of incoming protons from the matrix [114]. In addition, Tl + does not inhibit mitochondrial respiratory enzymes [9,10,24,25]. This is why Tl + increased state 4 respiration and did not affect state 3 or 3U DNP respiration in energized RLM [9,24,25,[114][115][116][117].…”

“…The cytoplasmic concentration of Ca 2+ and Na + increased, while that of K + fell due to the Tl + toxic influence on rat hepatocytes and cardiomyocytes [22,23]. Unlike bivalent heavy metals, Tl + does not have any noticeable effect on either mitochondrial respiratory enzymes (NADH-, succinate-, and malate-dehydrogenases) or mitochondrial thiol groups [9,10,[24][25][26]. Here, it must be emphasized that the complexation constants of Tl + with molecules with vicinal thiol groups turned out to be two orders of magnitude lower than those of ions of toxic heavy metals (Ag + , Hg 2+ , Cd 2+ , and Pb 2+ ) [27].…”

“…We have shown that excess Tl + ions moved from mitochondria when using a K + /H + exchanger, which is followed pumping out of incoming protons from the matrix [114]. In addition, Tl + does not mitochondrial respiratory enzymes [9,10,24,25]. This is why Tl + increased state 4 r tion and did not affect state 3 or 3UDNP respiration in energized RLM [9,24,25,114 As a similarly toxic heavy metal, Tl + increased the passive permeability of the IM univalent cations (K + , H + , and Na + ), and that was shown in experiments non-energized RLM injected into a nitrate medium containing a mixture of nitrate and one of the univalent cations [114].…”

“…The proximity of the crystal chemical radii of K + and Tl + allows the latter to use K + transport systems to enter the cell [6][7][8]. Na + /K + -ATPase, the Na + -K + -2Cl − cotransporter, and cellular membrane potassium channels are the main systems transporting Tl + ions into cells [9][10][11][12]. Easy polarizing, compared to K + , allows Tl + to form stronger chemical bonds with reactive electron donor groups of biological molecules (R-CO 2 − , R-OPO 3 2− , and R-SH).…”

“…The transport of K + was inhibited by Tl + in rat myocardial culture cells [14]. Tl + penetrated the cytoplasm and damaged cellular and mitochondrial membranes in omnifarious body organs [9,[15][16][17][18]. Thallium uncoupled oxidative phosphorylation in the mitochondria of mammalian cells [7,[19][20][21].…”