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Solubilization by CHAPS Detergent of Barbiturate‐Enhanced Benzodiazepine‐GABA Receptor Complex
Author(s) -
Stephenson F. Anne,
Olsen Richard W.
Publication year - 1982
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.1471-4159.1982.tb07990.x
Subject(s) - chemistry , chaps , flunitrazepam , gabaa receptor , barbiturate , benzodiazepine , chromatography , receptor , muscimol , dissociation constant , solubilization , biochemistry , pharmacology , medicine
Barbiturates enhance the binding of [ 3 H]flunitrazepam to benzodiazepine receptors solubilized with the detergent 3‐[(3‐cholamidopropyl)‐dimethylammonio]propanesulfonate (CHAPS) from bovine cortex. The enhancement by the barbiturates is seen as a decrease in the dissociation constant, K d , for specific benzodiazepine binding, with no effect on the number of binding sites. The effect of the barbiturates is facilitated by chloride ions, is concentration‐dependent, and has a specificity that correlates well with the anesthetic potency of barbiturates. [ 3 H]Flunitrazepam binding activity is stable with storage at 4°C., but barbiturate enhancement of soluble benzodiazepine binding activity decayed rapidly ( t 1/2 = 48 h). [ 3 H]Muscimol binding (GABA receptor) activity was also enhanced by barbiturates. Agarose gel filtration column chromatography of the CHAPS‐solubilized receptor proteins showed the same elution profile as receptors solubilized with sodium deoxycholate, and enhancement by barbiturates was observed for both the benzodiazepine and GABA binding activities.