Solubilisation of the gamma-aminobutyric acid/benzodiazepine receptor from rat cerebellum: optimal preservation of the modulatory responses by natural brain lipids.
We have solubilised the gamma-aminobutyric acid/benzodiazepine (GABA/BDZ) receptor from rat cerebellum using 3-[(3-cholamidopropyl)dimethylammonio] 1-propane sulphonate (CHAPS) in the presence of a natural brain lipid extract and cholesteryl hemisuccinate. The soluble material shows a homogeneous [3H]flunitrazepam ([3H]FNZ) binding population with an equilibrium dissociation constant (KD) of 4.4 +/- 0.2 nM compared to a KD of 2.3 +/- 0.2 nM in cerebellar synaptosomal membranes. The receptor complex in solution retains the characteristic facilitation of [3H]flunitrazepam binding induced by GABA, the pyrazolopyridine cartazolate, and the depressant barbiturate pentobarbital to the same extent as that observed in synaptosomal membranes. Furthermore, these responses are retained both quantitatively and qualitatively when this preparation is stored for 48 h at 4 degrees C. This is contrary to the results obtained with a CHAPS-soluble preparation including asolectin in which these responses are anomalous and extremely labile on storage.
Bristow
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DR
MRC Molecular Neurobiology Unit, University of Cambridge Medical School, England.
Martin
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D000818:Animals; D002531:Cerebellum / Q000032:analysis*; D002788:Cholesterol Esters / Q000494:pharmacology; D002793:Cholic Acids; D005445:Flunitrazepam / Q000378:metabolism; D008055:Lipids / Q000494:pharmacology*; D008297:Male; D010424:Pentobarbital / Q000494:pharmacology; D010743:Phospholipids; D011720:Pyrazoles / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D012995:Solubility; D012996:Solutions; D013025:Glycine max; D013570:Synaptic Membranes / Q000032:analysis; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D002788:Cholesterol Esters; D002793:Cholic Acids; D008055:Lipids; D010743:Phospholipids; D011720:Pyrazoles; D011963:Receptors, GABA-A; D012996:Solutions; D005680:gamma-Aminobutyric Acid; D005445:Flunitrazepam; C006315:cartazolate; D010424:Pentobarbital; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate; C013440:cholesteryl succinate