title: Effect of chronic morphine exposure on the synaptic plasma-membrane subproteome of rats: a quantitative protein profiling study based on isotope-coded affinity tags and liquid chromatography/mass spectrometry.
abstract: The effect of chronic morphine exposure on the synaptic plasma-membrane subproteome in rats was studied by the isotope-coded affinity tag (ICAT) method coupled with capillary reversed-phase liquid chromatography/electrospray ionization mass spectrometry and tandem mass spectrometry. ICAT-labeled tryptic peptides of synaptic membrane proteins were successfully identified using tandem mass spectrometry in conjunction with protein database searching. Several important synaptic plasma-membrane proteins displayed significant regulation changes as a result of chronic morphine exposure in vivo. In particular, an integral membrane protein Na(+)/K+ ATPase (alpha-subunit) involved in regulation of the cell membrane potential by controlling sodium and potassium ion permeability was downregulated by 39 +/- 2%. This result was in excellent agreement with the reduction in electrogenic Na+, K+ pumping due to about 40% downregulation of Na(+)/K+ ATPase alpha3-isoform in myenteric S-neurons of morphine-exposed guinea-pigs measured by others via immunohistochemistry. The decrease in the abundance of non-erythroid alpha II-spectrin in the synaptic plasma-membrane fraction was also observed, which was hypothetically associated with the breakdown of the protein due to the upregulation of the proteolytic enzyme caspase-3 upon chronic morphine exposure.
authors.affiliation: Department of Medicinal Chemistry, University of Florida, Gainesville, Florida 32610-0485, USA. lprokai@grove.ufl.edu
authors.forename: Laszlo
authors.initials: L
authors.lastname: Prokai
authors.forename: Alevtina D
authors.initials: AD
authors.lastname: Zharikova
authors.forename: Stanley M
authors.initials: SM
authors.lastname: Stevens
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D002853:Chromatography, Liquid; D002908:Chronic Disease; D007553:Isotope Labeling; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D009021:Morphine Dependence / Q000378:metabolism*; D010455:Peptides / Q000032:analysis; D016548:Prosencephalon / Q000378:metabolism*; D040081:Protein Array Analysis / Q000379:methods; D011506:Proteins / Q000032:analysis*; D040901:Proteomics / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D021241:Spectrometry, Mass, Electrospray Ionization; D013347:Subcellular Fractions / Q000378:metabolism; D013570:Synaptic Membranes / Q000378:metabolism*; D014357:Trypsin
chemical_list: D010455:Peptides; D011506:Proteins; D014357:Trypsin