Possible Allosteric Interaction of 4‐Aminopyridine with Rat Brain Muscarinic Acetylcholine Receptors

Wi S. Lai, Vickram Ramkumar, Esam E. El‐Fakahany

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


The interaction of the potassium channel blocker 4‐aminopyridine (4‐AP) and its analogs with muscarinic acetylcholine receptors was studied in rat brain homogenate. 4‐AP displaced specific [3H]quinuclidinyl benzilate ([3H]QNB) binding in a concentration‐dependent fashion. Hill coefficient values decreased with increasing the concentration of [3H]QNB and different analogs of 4‐AP demonstrated varying potencies. Scatchard analysis of saturation isotherms of specific [3H]QNB binding showed that low concentrations of 4‐AP slightly reduced maximum binding without affecting the equilibrium dissociation constant, whereas higher concentrations reduced maximum binding further and significantly increased the equilibrium dissociation constant. Schild plots of these data resulted in curvilinear functions. The results are discussed in terms of possible allosteric interactions between potassium channels and muscarinic receptor binding sites.

Original languageEnglish (US)
Pages (from-to)1936-1942
Number of pages7
JournalJournal of Neurochemistry
Issue number6
StatePublished - Jun 1985


  • 4‐Aminopyridine
  • Channel blockers
  • Muscarinic receptors
  • Potassium channels

Fingerprint Dive into the research topics of 'Possible Allosteric Interaction of 4‐Aminopyridine with Rat Brain Muscarinic Acetylcholine Receptors'. Together they form a unique fingerprint.

Cite this