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Solubilisation of the γ‐Aminobutyric Acid/Benzodiazepine Receptor from Rat Cerebellum: Optimal Preservation of the Modulatory Responses by Natural Brain Lipids
Author(s) -
Bristow David R.,
Martin Ian L.
Publication year - 1987
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1987.tb01004.x
Subject(s) - flunitrazepam , chemistry , dissociation constant , chaps , cerebellum , gabaa receptor , receptor , population , benzodiazepine , aminobutyric acid , pentobarbital , membrane , chromatography , biochemistry , pharmacology , neuroscience , biology , demography , sociology
We have solubilised the γ‐aminobutyric acid/ benzodiazepine (GABA/BDZ) receptor from rat cerebellum using 3‐[(3‐cholamidopropyl)dimethylammonio] l‐propane sulphonate (CHAPS) in the presence of a natural brain lipid extract and cholesteryl hemisuccinate. The soluble material shows a homogeneous [ 3 H]flunitrazepam ([ 3 H]FNZ) binding population with an equilibrium dissociation constant ( K D ) of 4.4 × 0.2 n M compared to a K D of 2.3 × 0.2 n M in cerebellar synaptosomal membranes. The receptor complex in solution retains the characteristic facilitation of [ 3 H]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°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.