Minocycline restores spatial but not fear memory in olfactory bulbectomized rats

Eur J Pharmacol. 2012 Dec 15;697(1-3):59-64. doi: 10.1016/j.ejphar.2012.09.005. Epub 2012 Oct 7.

Abstract

We investigated the effects of minocycline, a microglia suppressant, on olfactory bulbectomized (OBX) rats, a model of cognitive and behavioral impairments arising from neurodegenerative processes. Previously, we demonstrated that the major OBX-induced behavioral and cognitive impairments develop between day 3 and 7 following bulbectomy. Here we show that the onset of these cognitive changes parallel in time with signs of microglia activation (increased mRNA levels of IL-1β and CD68) in hippocampus. Next, rats were treated with minocycline (50mg/kg, i.p.) once daily for 4 weeks. OBX surgery was done at day 3 of drug treatment. Animals were tested in a battery of behavioral assays: open field, passive avoidance (fear learning and memory-acquired prior to OBX) and T-maze (spatial memory, conducted post bulbectomy). Minocycline normalized OBX-induced hyperactivity in the open field. Minocycline failed to prevent fear memory loss, but protected the OBX rats against hippocampal-dependent spatial memory deficit. Our findings suggest that treatment with minocycline may be effective in the early phase of a neurodegenerative disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, CD / genetics
  • Antigens, CD / metabolism
  • Antigens, Differentiation, Myelomonocytic / genetics
  • Antigens, Differentiation, Myelomonocytic / metabolism
  • Avoidance Learning / drug effects
  • Behavior, Animal / drug effects*
  • Cognition / drug effects
  • Cognition Disorders / drug therapy*
  • Cognition Disorders / etiology
  • Cognition Disorders / genetics
  • Cognition Disorders / psychology
  • Disease Models, Animal
  • Fear / drug effects*
  • Hippocampus / drug effects
  • Hippocampus / metabolism
  • Injections, Intraperitoneal
  • Interleukin-1beta / genetics
  • Interleukin-1beta / metabolism
  • Male
  • Memory / drug effects*
  • Memory Disorders / drug therapy*
  • Memory Disorders / etiology
  • Memory Disorders / genetics
  • Memory Disorders / psychology
  • Microglia / drug effects
  • Microglia / metabolism
  • Minocycline / administration & dosage
  • Minocycline / pharmacology*
  • Neuropsychological Tests
  • Nootropic Agents / administration & dosage
  • Nootropic Agents / pharmacology*
  • Olfactory Bulb / surgery*
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Time Factors
  • Up-Regulation

Substances

  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD68 protein, rat
  • Interleukin-1beta
  • Nootropic Agents
  • RNA, Messenger
  • Minocycline