Cholesterol depletion inhibits synaptic transmission and synaptic plasticity in rat hippocampus

Exp Neurol. 2008 Aug;212(2):407-14. doi: 10.1016/j.expneurol.2008.04.019. Epub 2008 Apr 25.

Abstract

Several neurodegenerative disorders are associated with impaired cholesterol homeostasis in the nervous system where cholesterol is known to play a role in modulating synaptic activity and stabilizing membrane microdomains. In the present report, we investigated the effects of methyl-beta-cyclodextrin-induced cholesterol depletion on synaptic transmission and on the expression of 1) paired-pulse facilitation (PPF); 2) paired-pulse inhibition (PPI) and 3) long-term potentiation (LTP) in the CA1 hippocampal region. Results demonstrated that cyclodextrin strongly reduced synaptic transmission and blocked the expression of LTP, but did not affect PPF and PPI. The role of glutamatergic and GABAergic receptors in these cholesterol depletion-mediated effects was evaluated pharmacologically. Data indicate that, in cholesterol depleted neurons, modulation of synaptic transmission and synaptic plasticity phenomena are sustained by AMPA-, kainate-and NMDA-receptors but not by GABA-receptors. The involvement of AMPA-and kainate-receptors was confirmed by fluorimetric analysis of intracellular calcium concentrations in hippocampal cell cultures. These data suggest that modulation of receptor activity by manipulation of membrane lipids is a possible therapeutic strategy in neurodegenerative disease.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Animals
  • Calcium / metabolism
  • Cells, Cultured
  • Cholesterol / deficiency*
  • Cyclodextrins / pharmacology
  • Dose-Response Relationship, Drug
  • Dose-Response Relationship, Radiation
  • Electric Stimulation / methods
  • Embryo, Mammalian
  • Excitatory Amino Acid Agonists / pharmacology
  • Fura-2
  • Hippocampus / cytology*
  • In Vitro Techniques
  • Long-Term Potentiation / drug effects
  • Long-Term Potentiation / physiology*
  • Long-Term Potentiation / radiation effects
  • Male
  • Neurons / physiology*
  • Rats
  • Rats, Wistar
  • Synaptic Transmission / physiology*
  • Time Factors
  • beta-Cyclodextrins / pharmacology

Substances

  • Cyclodextrins
  • Excitatory Amino Acid Agonists
  • beta-Cyclodextrins
  • methyl-beta-cyclodextrin
  • Cholesterol
  • Calcium
  • Fura-2