CGP 55845A: a potent antagonist of GABAB receptors in the CA1 region of rat hippocampus

Neuropharmacology. 1993 Oct;32(10):1071-3. doi: 10.1016/0028-3908(93)90073-c.


The new GABAB receptor antagonist CGP 55845A was tested on pre- and post-synaptic GABAB receptors in the hippocampus. CGP 55845A (1 microM) blocked (-)-baclofen (5-10 microM)-induced postsynaptic hyperpolarization and depression of evoked IPSPs and EPSPs. It also blocked three physiological consequences of GABAB receptor activation: the late IPSP, paired-pulse depression of IPSCs, and heterosynaptic depression of EPSPs. Therefore, CGP 55845A is an antagonist at pre- and post-synaptic GABAB receptors in the hippocampus and is approximately three orders of magnitude more potent than previously described GABAB receptor antagonists.

MeSH terms

  • Animals
  • Baclofen / antagonists & inhibitors
  • Baclofen / pharmacology
  • Evoked Potentials / drug effects
  • GABA-B Receptor Antagonists
  • Hippocampus / drug effects
  • Hippocampus / metabolism*
  • In Vitro Techniques
  • Phosphinic Acids / pharmacology*
  • Propanolamines / pharmacology*
  • Rats
  • Receptors, GABA-B*
  • Synapses / drug effects
  • Synapses / metabolism
  • gamma-Aminobutyric Acid / metabolism


  • GABA-B Receptor Antagonists
  • Phosphinic Acids
  • Propanolamines
  • Receptors, GABA-B
  • CGP 55845A
  • gamma-Aminobutyric Acid
  • Baclofen