Methamphetamine produces neuronal inclusions in the nigrostriatal system and in PC12 cells.
Mice treated with the psychostimulant methamphetamine (MA) showed the appearance of intracellular inclusions in the nucleus of medium sized striatal neurones and cytoplasm of neurones of the substantia nigra pars compacta but not in the frontal cortex. All inclusions contained ubiquitin, the ubiquitin activating enzyme (E1), the ubiquitin protein ligase (E3-like, parkin), low and high molecular weight heat shock proteins (HSP 40 and HSP 70). Inclusions found in nigral neurones stained for alpha-synuclein, a proteic hallmark of Lewy bodies that are frequently observed in Parkinson's disease and other degenerative disorders. However, differing from classic Lewy bodies, MA-induced neuronal inclusions appeared as multilamellar bodies resembling autophagic granules. Methamphetamine reproduced this effect in cultured PC12 cells, which offered the advantage of a simple cellular model for the study of the molecular determinants of neuronal inclusions. PC12 inclusions, similar to those observed in nigral neurones, were exclusively localized in the cytoplasm and stained for alpha-synuclein. Time-dependent experiments showed that inclusions underwent a progressive fusion of the external membranes and developed an electrodense core. Inhibition of dopamine synthesis by alpha-methyl-p-tyrosine (alphaMpT), or administering the antioxidant S-apomorphine largely attenuated the formation of inclusions in PC12 cells exposed to MA. Inclusions were again observed when alphaMpT-treated cells were loaded with l-DOPA, which restored intracellular dopamine levels.
Fornai
Francesco
F
Department of Human Morphology and Applied Biology, University of Pisa, Pisa, Italy. f.fornai@med.unipi.it
Lenzi
Paola
P
Gesi
Marco
M
Soldani
Paola
P
Ferrucci
Michela
M
Lazzeri
Gloria
G
Capobianco
Loredana
L
Battaglia
Giuseppe
G
De Blasi
Antonio
A
Nicoletti
Ferdinando
F
Paparelli
Antonio
A
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects* / Q000648:ultrastructure; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D002479:Inclusion Bodies / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D007980:Levodopa / Q000494:pharmacology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D017551:Microdialysis; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure*; D016716:PC12 Cells; D051381:Rats; D013378:Substantia Nigra / Q000187:drug effects* / Q000648:ultrastructure; D051843:Synucleins; D019805:alpha-Methyltyrosine / Q000494:pharmacology; D051844:alpha-Synuclein
D000975:Antioxidants; D000697:Central Nervous System Stimulants; D004791:Enzyme Inhibitors; D009419:Nerve Tissue Proteins; C497605:Snca protein, mouse; C497606:Snca protein, rat; D051843:Synucleins; D051844:alpha-Synuclein; D008694:Methamphetamine; D007980:Levodopa; D019805:alpha-Methyltyrosine; D004298:Dopamine