Amphetamine effects on brain protein structure and oxidative stress as revealed by FTIR microspectroscopy

Abstract

Amphetamines are psychostimulants abused by man, that eventually leads to drug dependence. Amphetamine administration to rodents has been shown to provoke significant neurotoxicity involving dopaminergic nerve terminal degeneration. However, little information related to the effect of amphetamines on reactive oxygen species (ROS) production and neurotoxicity in brain is currently available. Herein we report the biochemical alterations of lipids and proteins in brain sections from amphetamine‐treated rodents using infrared microspectroscopy, immunohistochemistry, and immunoblotting. The spectroscopic changes reveal for the first time the formation of β‐sheet‐rich proteins in the cortex, but no significant protein alterations are visible in hippocampus region where hydroperoxide concentration is found to be lower relative to cortex. These result suggest that ROS generated by amphetamine‐mediated oxidative stress induce formation β‐sheet‐rich proteins which can be of amyloid β‐like character. © 2007 Wiley Periodicals, Inc. Biopolymers 86: 437–446, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

FTIR microspectroscopic analysis of the effects of certain drugs on oxidative stress and brain protein structure

“…19 Briefly, infrared images were acquired with a liquid nitrogen cooled mercury cadmium telluride (MCT-A) line detector composed of 16 pixel elements, which can be operated either at 6.25 or 25 lm/pixel resolution. In this work, we used the 25 lm/pixel spatial resolution.…”

“…The Grams/AI software (ThermoGalactic) was used to fit the 1600-1500 cm 21 region to a sum of Lorentzian functions by a nonlinear least-squares procedure, to determine protein b-sheet contents as described elsewhere. 19 After atmospheric correction, all the spectra (in the 1000-700 cm 21 region) were converted to their second derivative using an 11-point Savitzky-Golay algorithm to minimize the influence of background artifacts. The resulting spectra in the above region were treated by principal component analysis (PCA).…”

“…Oxidative stress has been demonstrated to occur also in response to high doses of substituted amphetamines such as methamphetamine (METH) and 3,4-methlyenedioxymethamphetamine (MDMA) leading to long-term neurochemical changes. 19 Therefore, the spectroscopic measurement of peroxides in brain tissue samples is of interest to determine levels of the oxidative stress. Peroxide determinations can be carried out using various different ways.…”

“…Another alternative could be measurement of the CH stretching bands, because oxidation can result in disordering of the hydrocarbon lipid chains and subsequent increase of the corresponding half-band widths. 19 However, the mCH bands can be influenced by water to some extent, and their spectral changes are not necessarily produced just by lipid oxidation, but also by conformational transitions of membrane proteins and other membrane-related phenomena. Therefore, in fresh tissue samples it is necessary to find 550 Carmona et al…”

“…A previous study has demonstrated the potential of this spectroscopic technique in detecting amphetamine-induced oxidative stress and concomitant protein structural changes. 19 In this study, FTIR microspectroscopy has been used to investigate the molecular changes in brains from nicotine, D(1)-amphetamine, and nicotine and D(1)-amphetamine treated rats. Particularly, the use of this spectroscopic technique is focused here on protein structural changes and measurement of lipid peroxidation generated by the above drug treatments under conditions designed not to produce apoptosis.…”