Differential regulation of 'central' and 'peripheral' benzodiazepine binding sites in the rat olfactory bulb.
The density of [3H]flunitrazepam and [3H]Ro 5-4864 binding sites was examined 19-21 and 27-31 days after surgical isolation of the olfactory bulbs. While statistically significant reductions in [3H]flunitrazepam binding were observed in the olfactory bulbs at both intervals, a significant reduction in [3H]Ro 5-4864 binding was observed only at 27-31 days after surgery. No consistent changes in the binding of either radioligand were observed in cerebella. Extirpation of the olfactory bulbs resulted in a significant reduction in the convulsant potency (but not efficacy) of Ro 5-4864, while neither the potency nor efficacy of pentylenetetrazole was affected by this procedure. These results suggest that benzodiazepine receptors and 'peripheral-type' binding sites for benzodiazepines are regulated independently, and that at least a subpopulation of peripheral-type binding sites are associated with neuronal elements in the olfactory bulb. These data also suggest that peripheral-type binding sites for benzodiazepines in the olfactory bulbs may influence the convulsant actions of Ro 5-4864.
D000818:Animals; D001569:Benzodiazepines / Q000378:metabolism; D001570:Benzodiazepinones / Q000378:metabolism / Q000494:pharmacology; D002531:Cerebellum / Q000378:metabolism; D003292:Convulsants / Q000494:pharmacology; D005445:Flunitrazepam / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009830:Olfactory Bulb / Q000378:metabolism* / Q000502:physiology; D010433:Pentylenetetrazole / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000378:metabolism*
D001570:Benzodiazepinones; D003292:Convulsants; D011963:Receptors, GABA-A; D001569:Benzodiazepines; C028513:4'-chlorodiazepam; D005445:Flunitrazepam; D010433:Pentylenetetrazole