PT  - JOURNAL ARTICLE
AU  - Fuller, R W
AU  - Robertson, D W
AU  - Hemrick-Luecke, S K
TI  - Comparison of the effects of two 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine analogs, 1-methyl-4-(2-thienyl)-1,2,3,6-tetrahydropyridine and 1-methyl-4-(3-thienyl)-1,2,3,6-tetrahydropyridine, on monoamine oxidase in vitro and on dopamine in mouse brain.
DP  - 1987 Feb 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 415--420
VI  - 240
IP  - 2
4099  - http://jpet.aspetjournals.org/content/240/2/415.short
4100  - http://jpet.aspetjournals.org/content/240/2/415.full
SO  - J Pharmacol Exp Ther1987 Feb 01; 240
AB  - 1-Methyl-4-(2-thienyl)-1,2,3,6-tetrahydropyridine (2-MTTP) and 1-methyl-4-(3-thienyl)-1,2,3,6-tetrahydropyridine were compared with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) with respect to their interactions with MAO (monoamine oxidase) in vitro and their ability to produce persistent depletion of striatal dopamine and its metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, in mice. Both 2-MTTP and 1-methyl-4-(3-thienyl)-1,2,3,6-tetrahydropyridine were like MPTP in being potent, competitive inhibitors of MAO-A (MAO type A) and weak, noncompetitive inhibitors of MAO-B (MAO type B) in vitro. 2-MTTP resulted in persistent depletion of striatal dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid 1 week after the last of four daily injections to mice although 2-MTTP was less than one-fourth as potent as MPTP. The other isomer, 1-methyl-4-(3-thienyl)-1,2,3,6-tetrahydropyridine, failed to deplete dopamine or its metabolites in mouse striatum. Dopamine and its metabolites were also depleted in mouse nucleus accumbens by 2-MTTP and by MPTP; however, norepinephrine in frontal cortex was depleted by MPTP but not by 2-MTTP. The depletion of dopamine, 3,4-dihydroxyphenylacetic acid and homovanillic acid by 2-MTTP was prevented by pretreatment with deprenyl, a selective inhibitor of MAO-B, or with EXP 561, a dopamine uptake inhibitor, just as the depletion by MPTP was prevented. Mouse brain MAO oxidized 2-MTTP in vitro less rapidly than it oxidized MPTP; deprenyl was a potent inhibitor of the oxidation of both substrates, suggesting that MAO-B oxidizes both 2-MTTP and MPTP.(ABSTRACT TRUNCATED AT 250 WORDS)