Effect of synthetic purines and purine nucleosides on [3H]diazepam binding in brain.
We have compared fifteen synthetic purines and purine nucleosides on their ability to displace [3H]diazepam binding to rat brain membranes. Among these analogs, 6-methylthioguanine was found to be most potent, inhibiting competitively the specific binding of [3H]diazepam with a Ki value of 16 micro M. At a concentration of 50 micro M, 6-methyl-thioguanine increased tha apparent Kd of specific diazepam binding from 4.3 nM to 13.3 nM without affecting the Bmax, nor had it any effect on the non-specific binding. Binding with membrane preparations from developing rat brain was slightly less sensitive to 6-methylthioguanine inhibition than that with membranes prepared from mature brain.
D000375:Aging; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D003975:Diazepam / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008566:Membranes / Q000378:metabolism; D011684:Purine Nucleosides / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013574:Synaptosomes / Q000378:metabolism; D013866:Thioguanine / Q000031:analogs & derivatives / Q000494:pharmacology
D011684:Purine Nucleosides; D011687:Purines; C035366:6-methylthioguanine; D013866:Thioguanine; D003975:Diazepam