Immunohistochemical investigation of dopaminergic terminal markers and caspase-3 activation in the striatum of human methamphetamine users.
Methamphetamine (METH) has been shown to induce neurotoxicity. In a previous human study using quantitative Western blotting and radioligand binding assay, dopaminergic terminal marker deficits were induced in chronic METH users. In this study, we examined the suitability of the immunohistochemical detection of tyrosine hydroxylase (TH), dopamine transporter (DAT), and vesicular monoamine transporter-2 (VMAT2) levels, and caspase-3 activation in the striatum to diagnose METH abuse. Decreases in TH immunoreactivity in the nucleus accumbens and DAT in the nucleus accumbens and putamen were induced in METH users, whereas a significant difference of VMAT2 was not evident between METH and control groups. However, in the nucleus accumbens of two METH users, levels of VMAT2, a stable marker of striatal dopaminergic terminal integrity, were reduced remarkably. These findings might indicate that dopaminergic terminal degeneration is induced in the striatum of some METH abusers. On the other hand, we observed little caspase-3 activation, indicative of apoptosis, in the striatal neurons of chronic METH users. Overall, the findings of dopaminergic terminal markers were similar to those in the previous human study. Therefore, it is suggested that immunohistochemical techniques could be used to examine dopaminergic terminal marker levels and could also give useful information on chronic and/or lethal METH use in cases of METH-related death, where METH intoxication may not be toxicologically demonstrated.
Kitamura
Osamu
O
Department of Forensic Medicine, Institute of Health Bioscience, The University of Tokushima Graduate School, Tokushima, Japan. northv@basic.med.tokushima-u.ac.jp
Tokunaga
Itsuo
I
Gotohda
Takako
T
Kubo
Shin-ichi
S
D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000378:metabolism*; D001479:Basal Ganglia / Q000378:metabolism* / Q000473:pathology; D015415:Biomarkers / Q000378:metabolism; D016022:Case-Control Studies; D053148:Caspase 3 / Q000378:metabolism*; D015259:Dopamine Agents / Q000494:pharmacology; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D005260:Female; D053593:Forensic Toxicology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D050493:Vesicular Monoamine Transport Proteins / Q000378:metabolism
D015415:Biomarkers; D015259:Dopamine Agents; D050483:Dopamine Plasma Membrane Transport Proteins; D050493:Vesicular Monoamine Transport Proteins; D008694:Methamphetamine; D014446:Tyrosine 3-Monooxygenase; D053148:Caspase 3