title: Ascorbate induced lipid peroxidation results in loss of receptor binding in tris, but not in phosphate, buffer. Implications for the involvement of metal ions.
abstract: Rat brain homogenate was incubated with various concentrations of ascorbate in a Tris-HC1 buffer. Thiobarbituric acid-reactive substances (TBARS) were measured and 3H-QNB (quinuclidinyl benzilate) binding was also assayed on the same homogenate. Good parallelism between TBARS formation and loss of 3H-QNB binding activity confirmed that loss of 3H-QNB binding resulted from ascorbate-induced lipid peroxidation. However, neither formation of TBARS nor loss of 3H-QNB binding occurred in phosphate buffer or in the Tris-HC1 system in the presence of metal-chelating reagents. This indicates that phosphate addition prevents the ascorbate effects due to complete chelation of intrinsic metal ions.
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D001921:Brain / Q000378:metabolism*; D002021:Buffers; D004492:Edetic Acid / Q000494:pharmacology; D007700:Kinetics; D008054:Lipid Peroxides / Q000378:metabolism*; D008297:Male; D010710:Phosphates / Q000494:pharmacology*; D011812:Quinuclidines / Q000378:metabolism*; D011813:Quinuclidinyl Benzilate / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011976:Receptors, Muscarinic / Q000378:metabolism*; D013858:Thiobarbiturates; D014325:Tromethamine / Q000494:pharmacology*
chemical_list: D002021:Buffers; D008054:Lipid Peroxides; D010710:Phosphates; D011812:Quinuclidines; D011976:Receptors, Muscarinic; D013858:Thiobarbiturates; C028484:quinuclidinyl benzilate receptor; D014325:Tromethamine; D011813:Quinuclidinyl Benzilate; D004492:Edetic Acid; C029684:thiobarbituric acid; D001205:Ascorbic Acid