Interaction of barbiturates with benzodiazepine receptors in the central nervous system

Phil Skolnick, Kenner C. Rice, Jeffrey L. Barker, Steven M. Paul

Research output: Contribution to journalArticle

53 Scopus citations

Abstract

The interaction of barbiturates with benzodiazepine receptors was studied in extensively washed membrane preparations from rat brain. Sedative/hypnotic and anesthetic barbiturates such as pentobarbital, and convulsant barbiturates such as DMBB, enhanced [3H]diazepam binding in a stereospecific fashion. Freezethawing of membranes resulted in a decrease in the potency of barbiturates to enhance [3H]diazepam binding, while the maximum response to barbiturates remained unchanged. Significant differences in both the potency and maximum enhancement of [3H]diazepam binding by pentobarbital was observed among brain regions. The rank order potency of pentobarbital in different brain regions was: cerebellum > cortex > hippocampus, while the rank order efficacy of pentobarbital in these brain regions was reversed. The effects of a combination of anesthetic and/or convulsant barbiturates on [3H]diazepam binding suggested that these compounds function as partial agonists while a combination of anesthetic or convulsant barbiturates with phenobarbital suggested that the latter compound antagonized the actions of both anesthetic and convulsant barbiturates. The convulsant benzodiazepine Ro-5-3663 and inosine were more potent as inhibitors of pentobarbital-enhanced than basal (non-pentobarbital enhanced) [3H]diazepam binding. Solubilization of benzodiazepine receptors with Lubrol-PX resulted in a complete loss of barbiturate enhanced [3H]diazepam binding, and greater than a 75% loss in efficacy in the remaining (insoluble receptor) tissue.

Original languageEnglish
Pages (from-to)143-156
Number of pages14
JournalBrain Research
Volume233
Issue number1
DOIs
StatePublished - Feb 4 1982
Externally publishedYes

Keywords

  • DMBB
  • GABA
  • [H]diazepam
  • barbiturates
  • benzodiazepine receptors
  • pentobarbital

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