Increased sensitivity to the stimulant effects of morphine conferred by anti-adhesive glycoprotein SPARC in amygdala.
Repeated administration of morphine substantially increases its locomotor-enhancing activity, a phenomenon termed locomotor sensitization. Here we show that secreted protein acidic and rich in cysteine (SPARC), an anti-adhesive glycoprotein present in the basolateral amygdala, contributes to the establishment of locomotor sensitization. The morphine-induced increase in SPARC levels in the basolateral amygdala persisted after morphine withdrawal and coincided with the duration of locomotor sensitization. Moreover, a single injection of morphine after SPARC infusion into the basolateral amygdala of previously uninjected mice substantially enhanced locomotor activity. Thus, SPARC may be an important element for establishing locomotor sensitization to morphine.
Department of Biomolecular Engineering, National Institute of Bioscience and Human Technology, Agency of Industrial Science and Technology, Ministry of International Trade and Industry 1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan. ikemoto@nibh.go.jp
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D000679:Amygdala / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001483:Base Sequence; D002448:Cell Adhesion; D017931:DNA Primers / Q000235:genetics; D004361:Drug Tolerance; D008297:Male; D051379:Mice; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D015676:Osteonectin / Q000008:administration & dosage / Q000235:genetics / Q000494:pharmacology*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000494:pharmacology; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology; D015854:Up-Regulation
D017931:DNA Primers; D015676:Osteonectin; D011993:Recombinant Fusion Proteins; D009020:Morphine