Nuclear benzodiazepine binding: Possible interaction with thyroid hormone receptors
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- Dalezios, Y. & Matsokis, N. Neurochem Res (1993) 18: 305. doi:10.1007/BF00969087
The biochemical and pharmacological properties of nuclear [3H]flunitrazepam in brain tissues were studied. Nuclear [3Hflunitrazepam binding is saturable for both central and peripheral binding sites. Inosine and hypoxanthine displace nuclear [3H]flunitrazepam binding with greater potency than the membrane [3H]flunitrazepam binding. Triiodothyronine (T3) increases the maximum number of binding sites (Bmax) of nuclear [3H]flunitrazepam binding in vitro while thyroxine (T4) does not have any effect. Diazepam reduces the affinity of nuclear125I-T3 binding in vitro, while the Bmax is not affected significantly. Mild digestion of chromatin, using micrococcal nuclease, reveals that a major portion of nuclear [3H]flunitrazepam binding sites are located on chromatin. These data suggest a functional role for nuclear benzodiazepine binding and a possible modulatory effect of benzodiazepines on T3 binding with its nuclear receptors.