[3H]diazepam specific binding to rat cortex in vitro is enhanced by oleic, arachidonic and docosahexenoic acid isolated from pig brain.

Substances were found in purified fractions from pig brain that enhanced the specific binding of [3H]diazepam to membranes from rat brain in vitro. These substances were identified as oleic acid, arachidonic acid and docosahexenoic acid. Oleic acid (10(-5) - 10(-4)M) increased the affinity for agonists binding to the benzodiazepine receptor, whereas the binding of antagonists to this receptor was only slightly enhanced. The number of [3H]muscimol binding sites was increased, whereas binding of [3H]SR 95331, a GABA receptor antagonist, was unchanged. The effect of oleic acid was additional to the GABA-induced enhancement of [3H]diazepam binding.