Characterization of the neurotoxic potential of m-methoxy-MPTP and the use of its N-ethyl analogue as a means of avoiding exposure to a possible Parkinsonism-causing agent.
1-Methyl-4-(3-methoxyphenyl)-1,2,3,6-tetrahydropyridine (2) produced persistent depletion of striatal dopamine in mice after four daily injections, although it was less potent than 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP has been implicated as a cause of Parkinsonism in drug abusers who inadvertently self-administered it and in industrial chemists who were exposed to it. Our results suggest that the m-methoxy compound has the same neurotoxic potential to cause destruction of nigrostriatal dopamine neurons that would lead to Parkinsonian symptoms in humans. In contrast, 1-ethyl-4-(3-methoxyphenyl)-1,2,3,6-tetrahydropyridine (11) had no effects on striatal dopamine in mice, even at doses 8 times those of MPTP. A method of preparing 11 and using it as an intermediate in the synthesis of potential analgesic drugs, thus avoiding a potentially neurotoxic intermediate, is described.
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000031:analogs & derivatives; D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000187:drug effects*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D006719:Homovanillic Acid / Q000378:metabolism; D051379:Mice; D010302:Parkinson Disease, Secondary / Q000139:chemically induced*; D011725:Pyridines / Q000138:chemical synthesis / Q000494:pharmacology* / Q000633:toxicity; D013329:Structure-Activity Relationship
D011725:Pyridines; D015102:3,4-Dihydroxyphenylacetic Acid; C049795:1-ethyl-4-(3-methoxyphenyl)-1,2,3,6-tetrahydropyridine; C049794:1-methyl-4-(3-methoxyphenyl)-1,2,3,6-tetrahydropyridine; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D004298:Dopamine; D006719:Homovanillic Acid