[Interaction of thiamine with rat brain synaptosomes].
Thiamine has been shown to be bound specifically by a synaptosomal plasmatic membrane and transported inside to the nervous ending. Apparent K[symbol: see text] and Km for processes of binding and transport have been determined as equal 2.34 +/- 0.55 MKM and 3.92 +/- 1.3 MKM, respectively. The thiamine uptake by the isolated nervous endings (synaptosomes) at its physiological concentration is reduced in presence of metabolic inhibitors and partially depends on Mg2+ and Ca2+ ions, that can testify about the interrelation between endogenic thiamine phosphorilation and its transport through the membrane. Thiamine binding with synaptosomes is inhibited by ouabain and neurotoxins such as, latrotoxin and most significantly--with veratridin; tetrodotoxin fail to be efficient practically. In the conditions of synaptic membranes depolarisation their ability to bind thiamine is reduced and output of already uptaken with synaptosomes thiamine is observed.
Protasova
Z S
ZS
A.V. Palladin Institute of Biochemistry of Ukraine NAS, Kyiv.
Parkhomenko
Iu M
IuM
Donchenko
G V
GV
Churilova
T Ia
TIa
D000818:Animals; D001692:Biological Transport; D001921:Brain / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D013111:Spider Venoms / Q000494:pharmacology; D013574:Synaptosomes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D013779:Tetrodotoxin / Q000494:pharmacology; D013831:Thiamine / Q000378:metabolism / Q000494:pharmacology*; D014701:Veratridine / Q000494:pharmacology
D013111:Spider Venoms; D013779:Tetrodotoxin; D010042:Ouabain; C020763:alpha-latrotoxin; D014701:Veratridine; D000254:Sodium-Potassium-Exchanging ATPase; D013831:Thiamine