Bicuculline-insensitive GABA receptors: studies on the binding of (-)-baclofen to rat cerebellar membranes

Neurosci Lett. 1984 Dec 21;52(3):317-21. doi: 10.1016/0304-3940(84)90181-2.


The binding of [3H](-)-baclofen to synaptic membranes prepared from rat cerebellum was studied. Consistent with pharmacological data that (-)-baclofen is the more active stereoisomer, studies on the binding of [3H](-)-baclofen showed increased specific binding, a higher affinity Kd and a lower Bmax than equivalent studies using [3H](+/-)-baclofen. Divalent metal ions (mercury, lead, calcium and zinc) inhibited the binding of [3H](-)-baclofen. The effects of some conformationally restricted analogues of gamma-aminobutyric acid (GABA) on [3H](-)-baclofen binding indicated that GABA interacts with (-)-baclofen-sensitive binding sites (GABAB) in extended rather than folded conformations, and that folded analogues of GABA may interact with a class of binding site (GABAc?) insensitive to (-)-baclofen and bicuculline.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Baclofen / metabolism*
  • Bicuculline / pharmacology*
  • Cations, Divalent / pharmacology
  • Cerebellum / metabolism*
  • Kinetics
  • Rats
  • Receptors, GABA-A / drug effects
  • Receptors, GABA-A / metabolism*
  • Synaptic Membranes / metabolism
  • gamma-Aminobutyric Acid / analogs & derivatives
  • gamma-Aminobutyric Acid / pharmacology


  • Cations, Divalent
  • Receptors, GABA-A
  • gamma-Aminobutyric Acid
  • Baclofen
  • Bicuculline