In vitro antagonism of benzodiazepine binding to cerebral receptors by H 1 and H 2 antihistamines

K. V. Speeg, S. Wang, G. R. Avant, R. Parker, S. Schenker

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Antihistamines directed at either the H 1 or H 2 histamine receptor have the well-known side effect of sedation. The mechanism for the CNS depressant action of antihistamines is unknown. We examine here the possibility that the mechanism may involve modulation of the cerebral benzodiazepine receptor. We demonstrate that cimetidine and pyrilamine are competitive antagonists of 3H-benzodiazepine binding to human cerebral receptor in vitro. The inhibition of radioligand binding was not specific for benzodiazepine receptor, however, since antihistamines also antagonized binding to GABA, opiate, and muscarinic acetylcholine receptor. The interaction of antihistamine with CNS receptors other than histamine receptor may explain, at least in part, the side effect of sedation.

Original languageEnglish (US)
Pages (from-to)112-122
Number of pages11
JournalJournal of Laboratory and Clinical Medicine
Issue number1
StatePublished - 1981
Externally publishedYes

ASJC Scopus subject areas

  • Pathology and Forensic Medicine


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