Effect of picrotoxin on benzodiazepine receptors and GABA receptors with reference to the effect of C1- ion

Picrotoxin does not by itself affect [³H] diazepam binding to synaptosomal membranes of rat cerebellum; however, picrotoxin stimulated the binding in the presence of Cl^? ion or Cl^? ion plus low concentrations of GABA. On the other hand, in the presence of GABA at concentrations higher than 1 × 10^?6 M, picrotoxin inhibited [³H]diazepam binding. This inhibition seems to be the result of reduced GABA binding, which occurred in the presence of picrotoxin and Cl^? ion. These results may indicate that benzodiazepine receptors, GABA receptors, and the Cl^? ionophore are closely associated with each other.