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Temperature Dependence of [ 3 H]Ro 15–1788 Binding to Benzodiazepine Receptors in Human Postmortem Brain Homogenates
Author(s) -
Kopp Jutta,
Hall Håkan,
Persson Anders,
Sedvall Göran
Publication year - 1990
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.1471-4159.1990.tb03140.x
Subject(s) - neocortex , in vivo , receptor , human brain , in vitro , dissociation constant , gabaa receptor , chemistry , cerebellum , binding site , biophysics , endocrinology , biochemistry , medicine , biology , neuroscience , microbiology and biotechnology
The temperature dependence of in vitro binding of [ 3 H]Ro 15–1788 to benzodiazepine receptors in human postmortem neocortex and neocerebellum homogenates was studied. An increase of the equilibrium dissociation constants ( K D ) from 1.40 nmol/L and 1.04 nmol/L at 4°C to 6.10 nmol/L and 8.91 nmol/L at 37°C was found for neocortex and neocerebellum, respectively. In contrast, maximal binding ( B max ) remained in the range of 30–35 fmol/mg for neocortex and 24–27 fmol/mg of tissue (wet weight) for neocerebellum at all the temperatures. The K D of 6.10 nmol/L for neocortex at 37°C in vitro is of the same order as the K D of 10 nmol/L obtained by positron emission tomography for [ 11 C]Ro 15–1788 binding to benzodiazepine receptors in the human neocortex in vivo. The differences in K D between in vitro and in vivo benzodiazepine receptor binding to human neocortex and cerebellum seem to be due at least partially to temperature differences of in vitro and in vivo studies.