Proteomic analysis of rat cerebral cortex, hippocampus and striatum after exposure to morphine

Abstract

Abstract. Although a series of proteins in the brain have been shown to be qualitatively or quantitatively dysregulated following morphine administration, a systematic proteomic study has not been carried out so far. We therefore aimed to show the effect of morphine on protein levels in the rat brain. For this purpose rats were given a morphine base in subcutaneously placed pellets and subsequently the cerebral cortex, hippocampus and striatum were taken for proteomic studies after three days. Extracted proteins were run on twodimensional gel electrophoresis, scanned and quantified by specific software. Proteins with significantly different levels were analysed by mass spectrometry (MALDI-TOF-TOF). Twenty-six proteins were found to be differentially expressed and were unambiguously identified. Dysregulated proteins were from several protein pathways and cascades including signaling, metabolic, protein handling, antioxidant and miscellaneous classes. These findings represent an initial approach to the generation of a 'morphinome' and may form the basis for further protein chemical studies as a valuable analytical tool. Moreover, the study reveals morphine-regulated proteins in different brain areas and indicates the pathways involved following morphine administration in the rat, the main species for pharmacological studies in the field.

Proteomic analysis of striatal neuronal cell cultures after morphine administration

“…In this case, the cell culture assures significant simplification of the sample and may allow for observation of low abundance proteins. This feature is clearly visible when we compared results obtained for beta-actin during a morphinome study in the brain [2], striatum [4], nucleus accumbens [5], and on the neuronal striatal cell culture level from our study. Changes in protein quantity are undetectable in morphinome from brain and striatum, probably due to the complexity of the samples.…”

“…Sample preparation for 2-DE was performed as described elsewhere [4]. Briefly, rat striatal neurons were suspended in 1 mL of sample buffer containing 7 M urea, 2 M thiourea, 4% CHAPS, 10 mM DTT, 1 mM EDTA, 1 mM phenylmethylsulfonyl fluoride (PMSF) and a mixture of protease inhibitors (Roche Diagnostics, Mannheim, Germany), sonicated on ice (4 cycles for 0.03 min), and left for 1 h at room temperature in darkness to allow each constituent of the samples to solubilize.…”

“…Proteome changes after morphine administration have hitherto been investigated mostly in the whole brain [2] and its structures involved in phenomena of addiction and reward mechanisms, such as the prefrontal cortex [3,4], hippocampus, striatum [4], nucleus accumbens [5], and in cellular fractions such as synaptosomes [6] and postsynaptic densities [7].…”

Genes and Pathways Co-associated with the Exposure to Multiple Drugs of Abuse, Including Alcohol, Amphetamine/Methamphetamine, Cocaine, Marijuana, Morphine, and/or Nicotine: a Review of Proteomics Analyses

“…Although they are still evolving technologies, proteomics approaches have become useful tools for elucidating the molecular effects of addictive substances. In past years, proteomics has been used to profile the protein expression pattern in cultured neurons or different brain regions of animals or humans in response to a number of substances of abuse such as nicotine, amphetamine, alcohol, cocaine, and morphine [11][12][13][14][15].…”

Transient Receptor Potential Vanilloid Type 1 Channel May Modulate Opioid Reward

“…Repeated morphine exposure alters gene expression and subsequently induces stable changes in protein components (Ammon-Treiber and Hollt, 2005). There is mounting evidence suggesting that the alteration of protein profiles in the brain after repeated morphine exposure underlie morphine addiction (Bierczynska-Krzysik et al, 2006;Kim et al, 2005;Li et al, 2006a). Numerous proteins that change their expression pattern following morphine treatment are listed in these publications, but particular candidate proteins for morphine reward-related proteins have not been evaluated.…”