title: Inhibitory characteristics of styrene & styrene oxide on Na+,K+ activated adenosine triphosphatase.
abstract: Styrene, an important ingredient of plastic, is reported to cause it neurotoxic effects through its important metabolite styrene oxide. Na+, K+ -ATPase (NKA), an important enzyme in the neurotransmission processes, is found to be inhibited by styrene (200 mg/kg) and styrene oxide (55 mg/Kg) by 15 and 45% respectively. Kinetic evaluations show that Km values, number of interaction sites and rate of reaction, with respect to K+ ions, decreased in styrene oxide treated NKA samples. However, high Km values of Na+ sites suggest for low affinity with respect to Na+ ions. Na+ and K+ ion activation, ATP hydrolysis and ouabain titration patterns indicate for a conformational change in NKA mainly due to styrene oxide.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D004852:Epoxy Compounds / Q000494:pharmacology*; D004988:Ethers, Cyclic / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020058:Styrene; D013343:Styrenes / Q000494:pharmacology*; D013574:Synaptosomes / Q000187:drug effects* / Q000201:enzymology
chemical_list: D004852:Epoxy Compounds; D004988:Ethers, Cyclic; D013343:Styrenes; D020058:Styrene; D010042:Ouabain; C013690:styrene oxide; D000254:Sodium-Potassium-Exchanging ATPase