Improved specificity of hippocampal memory trace labeling

Hippocampus. 2016 Jun;26(6):752-62. doi: 10.1002/hipo.22556. Epub 2016 Jan 20.

Abstract

Recent studies have focused on the identification and manipulation of memory traces in rodent models. The two main mouse models utilized are either a CreER(T2) /loxP tamoxifen (TAM)- or a tetracycline transactivator/tetracycline-response element doxycycline-inducible system. These systems, however, could be improved to label a more specific population of activated neurons corresponding to behavior. Here, we sought to identify an improved selective estrogen receptor (ER) modulator (SERM) in which we could label an individual memory trace in ArcCreER(T2) mice. We found that 4-hydroxytamoxifen (4-OHT) is a selective SERM in the ArcCreER(T2) × Rosa26-CAG-stop(flox) -channelrhodospin (ChR2)-enhanced yellow fluorescent protein (eYFP) mice. The half-life of 4-OHT is shorter than TAM, allowing for more specificity of memory trace labeling. Furthermore, 4-OHT allowed for context-specific labeling in the dentate gyrus and CA3. In summary, we believe that 4-OHT improves the specificity of memory trace labeling and will allow for refined memory trace studies in the future. © 2015 Wiley Periodicals, Inc.

Keywords: Arc; Hippocampus; c-fos; learning; memory.

MeSH terms

  • Animals
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Cell Count
  • Channelrhodopsins / genetics
  • Channelrhodopsins / metabolism
  • Conditioning, Psychological / physiology
  • Estradiol / analogs & derivatives
  • Fear / physiology
  • Fulvestrant
  • Hippocampus / cytology
  • Hippocampus / metabolism*
  • Immunohistochemistry
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Memory / physiology*
  • Mice, Transgenic
  • Microscopy, Confocal
  • Models, Animal*
  • Neurons / cytology
  • Neurons / metabolism*
  • RNA, Untranslated / genetics
  • RNA, Untranslated / metabolism
  • Raloxifene Hydrochloride
  • Receptors, Estrogen / genetics
  • Receptors, Estrogen / metabolism
  • Selective Estrogen Receptor Modulators
  • Tamoxifen / analogs & derivatives

Substances

  • Bacterial Proteins
  • Channelrhodopsins
  • Gt(ROSA)26Sor non-coding RNA, mouse
  • Luminescent Proteins
  • RNA, Untranslated
  • Receptors, Estrogen
  • Selective Estrogen Receptor Modulators
  • yellow fluorescent protein, Bacteria
  • Tamoxifen
  • afimoxifene
  • Fulvestrant
  • Raloxifene Hydrochloride
  • Estradiol