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THE ELEVATION OF CEREBRAL HISTAMINE‐ N ‐AND CATECHOL‐ O ‐METHYL TRANSFERASE ACTIVITIES BY l ‐METHIONINE‐dl‐ SULFOXIMINE 1
Author(s) -
Schatz R. A.,
Sellinger O. Z.
Publication year - 1975
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1975.tb07696.x
Subject(s) - methionine , convulsant , transferase , histamine , guinea pig , catechol , histamine n methyltransferase , methyltransferase , chemistry , in vitro , biochemistry , catechol o methyl transferase , enzyme , methylation , biology , pharmacology , endocrinology , amino acid , histamine h2 receptor , receptor , allele , gene , antagonist
— The administration of the convulsant, l ‐methionine‐dl‐sulfoximine (MSO), increased histamine N ‐methyl transferase (E.C. 2.1.1.8) (HMT) activity in rat and mouse brain and, to a lesser extent, catechol‐ O ‐methyl transferase (E.C. 2.1.1.6) (COMT) activity in rat brain. The duration of this effect was shortened by co‐administration of l ‐methionine. The increased HMT activity was seen in 5 or 7 rat brain regions tested. l ‐Methionine administration had no effect on the activity of either enzyme. Partially purified HMT preparations from rat or guinea‐pig brain exhibited no alterations in activity after the in vitro addition of MSO or l ‐methionine over a wide range of histamine and S ‐adenosyl‐ l ‐methionine concentrations. Rat brain COMT was equally unaffected by MSO and l ‐methionine. The in vitro inhibition of HMT and COMT by S ‐adenosyl‐ l ‐homocysteine was the same whether tested on preparations derived from MSO‐treated or control animals. The data are discussed with respect to the possible involvement of aberrant methylation processes in the MSO‐induced seizure.