gamma-Aminobutyric acid: temperature dependence in benzodiazepine receptor binding.
The effects of muscimol and/or incubation temperature on the inhibition of [3H]flunitrazepam receptor binding by benzodiazepine receptor ligands were investigated. At 0 degree C muscimol decreased the Ki values for some ligands as displacers of [3H]flunitrazepam binding to brain-specific sites while increasing or having no effect on the Ki values for other ligands. The Ki values for some ligands are higher at 37 degrees C than at 0 degree C but are reduced by muscimol at both 0 degrees and 37 degrees C. In contrast, the ligands whose Ki values are increased by muscimol either decreased or did not alter the Ki values at 37 degrees C as compared to those at 0 degree C. Incubation of membranes at 37 degrees C for 30 min accelerated gamma-aminobutyric acid (GABA) release by 221% over that at 0 degree C. These results indicate that changes in incubation temperature alter benzodiazepine receptor affinity for ligands via GABA.
Chweh
A Y
AY
Swinyard
E A
EA
Wolf
H H
HH
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D004027:Diencephalon / Q000378:metabolism; D005445:Flunitrazepam / Q000378:metabolism; D051379:Mice; D009118:Muscimol / Q000494:pharmacology; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism*; D013687:Telencephalon / Q000378:metabolism; D013696:Temperature; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D014151:Anti-Anxiety Agents; D011963:Receptors, GABA-A; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D005445:Flunitrazepam