Molecular heterogeneity of benzodiazepine receptors

Nature. 1980 Jul 17;286(5770):285-7. doi: 10.1038/286285a0.

Abstract

Benzodiazepines exhibit reversible, stereospecific high affinity binding to mammalian brain membranes, and the respective binding sites for 3H-flunitrazepam represent pharmacologically and clinically relevant receptors for benzodiazepines. Recently it has been demonstrated that reversibly bound 3H-flunitrazepam becomes irreversibly attached to a specific membrane protein with apparent molecular weight of 50,000 when incubations are performed in the presence of UV light. Irreversible binding of 3H-flunitrazepam to this protein had pharmacological properties similar to reversible benzodiazepine receptor binding, indicating that 3H-flunitrazepam is a photoaffinity label for the benzodiazepine receptor. Using irreversible binding of 3H-flunitrazepam and subsequent electrophoretic separation of the labelled proteins in SDS-gels followed by fluorography, we found that in hippocampus and several other brain regions at least two different types of benzodiazepine receptors exist. Each seems to be associated with a gamma-aminobutyric acid (GABA) receptor.

MeSH terms

  • Animals
  • Benzodiazepines / metabolism*
  • Brain / metabolism*
  • Cerebellum / metabolism
  • Flunitrazepam / metabolism
  • Hippocampus / metabolism
  • Membrane Proteins / metabolism
  • Molecular Weight
  • Nerve Tissue Proteins / metabolism
  • Rats
  • Receptors, Drug / metabolism*
  • Receptors, GABA-A
  • Receptors, Neurotransmitter / metabolism*
  • gamma-Aminobutyric Acid / metabolism*

Substances

  • Membrane Proteins
  • Nerve Tissue Proteins
  • Receptors, Drug
  • Receptors, GABA-A
  • Receptors, Neurotransmitter
  • Benzodiazepines
  • gamma-Aminobutyric Acid
  • Flunitrazepam