Effects of antihistamines on the function of human α7-nicotinic acetylcholine receptors

Bassem Sadek, Seyedeh Soha Khanian, Abrar Ashoor, Tatiana Prytkova, Mohammad A. Ghattas, Noor Atatreh, Syed M. Nurulain, Keun Hang Susan Yang, Frank Christopher Howarth, Murat Oz

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Effects of the histamine H1 receptor (H1R) antagonists (antihistamines), promethazine (PMZ), orphenadrine (ORP), chlorpheniramine (CLP), pyrilamine (PYR), diphenhydramine (DPH), citerizine (CTZ), and triprolidine (TRP) on the functional properties of the cloned α7 subunit of the human nicotinic acetylcholine receptor expressed in Xenopus oocytes were investigated. Antihistamines inhibited the α7-nicotinic acetylcholine receptor in the order PYR>CLP>TRP>PMZ>ORP≥DPH≥CTZ. Among the antihistamines, PYR showed the highest reversible inhibition of acetylcholine (100 μM)-induced responses with IC50 of 6.2 μM. PYR-induced inhibition was independent of the membrane potential and could not be reversed by increasing the concentration of acetylcholine. Specific binding of [125I] α-bungarotoxin, a selective antagonist for α7-nicotinic acetylcholine receptor, was not changed in the presence of PYR suggesting a non-competitive inhibition of nicotinic receptors. In line with functional experiments, docking studies indicated that PYR can potentially bind allosterically with the α7 transmembrane domain. Our results indicate that the H2-H4 receptor antagonists tested in this study (10 μM) showed negligible inhibition of α7-nicotinic acetylcholine receptors. On the other hand, H1 receptor antagonists inhibited the function of human α7-nicotinic acetylcholine receptor, with varying potencies. These results emphasize the importance of α7-nicotinic acetylcholine receptor for future pharmacological/toxicological profiling.

Original languageEnglish
Pages (from-to)308-316
Number of pages9
JournalEuropean Journal of Pharmacology
Publication statusPublished - Jan 5 2015


  • Antihistamine
  • Nicotinic acetylcholine receptor
  • Pyrilamine
  • Xenopus oocyte

ASJC Scopus subject areas

  • Pharmacology


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