Chronic pregabalin inhibits synaptic transmission between rat dorsal root ganglion and dorsal horn neurons in culture

Channels (Austin). Mar-Apr 2012;6(2):124-32. doi: 10.4161/chan.19805. Epub 2012 Mar 1.

Abstract

In this study, we have examined the properties of synaptic transmission between dorsal root ganglion (DRG) and dorsal horn (DH) neurons, placed in co-culture. We also examined the effect of the anti-hyperalgesic gabapentinoid drug pregabalin (PGB) at this pharmacologically relevant synapse. The main method used was electrophysiological recording of excitatory post synaptic currents (EPSCs) in DH neurons. Synaptic transmission between DRG and DH neurons was stimulated by capsaicin, which activates transient receptor potential vanilloid-1 (TRPV1) receptors on small diameter DRG neurons. Capsaicin (1 μM) application increased the frequency of EPSCs recorded in DH neurons in DRG-DH co-cultures, by about 3-fold, but had no effect on other measured properties of the EPSCs. There was also no effect of capsaicin in the absence of co-cultured DRGs. Application of PGB (100 μM) for 40-48 h caused a reduction in the capsaicin-induced increase in EPSC frequency by 57%. In contrast, brief preincubation of PGB had no significant effect on the capsaicin-induced increase in EPSC frequency. In conclusion, this study shows that PGB applied for 40-48 h, but not acute application inhibits excitatory synaptic transmission at DRG-DH synapses, in response to nociceptive stimulation, most likely by a presynaptic effect on neurotransmitter release from DRG presynaptic terminals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analgesics / pharmacology*
  • Animals
  • Calcium / metabolism
  • Capsaicin / pharmacology
  • Coculture Techniques
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / physiology*
  • Microscopy, Fluorescence
  • Patch-Clamp Techniques
  • Posterior Horn Cells / cytology
  • Posterior Horn Cells / physiology*
  • Pregabalin
  • Rats
  • Rats, Sprague-Dawley
  • Sensory System Agents / pharmacology
  • Synaptic Potentials / drug effects*
  • Synaptic Transmission / drug effects*
  • TRPV Cation Channels / agonists
  • gamma-Aminobutyric Acid / analogs & derivatives*
  • gamma-Aminobutyric Acid / pharmacology

Substances

  • Analgesics
  • Sensory System Agents
  • TRPV Cation Channels
  • TRPV1 receptor
  • Pregabalin
  • gamma-Aminobutyric Acid
  • Capsaicin
  • Calcium