Post-training cocaine exposure facilitates spatial memory consolidation in C57BL/6 mice.

Academic Article


  • In this study, we examined the ability of post-training injections of cocaine to facilitate spatial memory performance using the Morris water maze (MWM). We also investigated the role that hippocampal protein kinase A (PKA) and extracellular signal-regulated kinase 1/2 (ERK) signaling may play in cocaine-mediated spatial memory consolidation processes. Male and female C57BL/6 mice were first trained in a MWM task (eight consecutive trials) then injected with cocaine (0, 1.25, 2.5, 5, or 20 mg/kg), and memory for the platform location was retested after a 24 h delay. Cocaine had a dose-dependent effect on spatial memory performance because only the mice receiving 2.5 mg/kg cocaine displayed a significant reduction in latency to locate the platform. No sex differences in MWM performance were observed; however, females showed higher hippocampal levels of PKA when compared with males. A second experiment demonstrated that 2.5 mg/kg cocaine enhanced MWM performance only when administered within 2, but not 4 h after spatial training. We also found that cocaine (2.5 mg/kg) increased ERK2 phosphorylation within the hippocampus and one of its downstream targets (ribosomal S6 kinase), a mechanism that may be responsible, at least in part, for the enhanced cocaine-mediated spatial memory performance. Overall, these data demonstrate that a low dose of cocaine (2.5 mg/kg) administered within 2 h after training facilitates MWM spatial memory performance in C57BL/6 mice.
  • Authors

  • Iñiguez, Sergio D
  • Charntikov, Sergios
  • Baella, Shelley A
  • Herbert, Matthew S
  • Bolaños-Guzmán, Carlos A
  • Crawford, Cynthia A
  • Status

    Publication Date

  • April 2012
  • Published In

  • Hippocampus  Journal
  • Keywords

  • Animals
  • Cocaine
  • Cyclic AMP-Dependent Protein Kinases
  • Dose-Response Relationship, Drug
  • Female
  • Hippocampus
  • MAP Kinase Signaling System
  • Male
  • Maze Learning
  • Memory
  • Mice
  • Mice, Inbred C57BL
  • Phosphorylation
  • Ribosomal Protein S6 Kinases
  • Time Factors
  • Digital Object Identifier (doi)

    Start Page

  • 802
  • End Page

  • 813
  • Volume

  • 22
  • Issue

  • 4