Characterization of the irreversible inhibition of high-affinity choline transport produced by hemicholinium mustard

J Neurochem. 1992 Oct;59(4):1302-8. doi: 10.1111/j.1471-4159.1992.tb08441.x.


The inhibition of high-affinity choline transport by hemicholinium mustard (HCM), an alkylating analogue of hemicholinium-3, was examined in rat brain synaptosomes and guinea pig myenteric plexus. In synaptosomes, 50% high-affinity choline transport inhibition occurs with an HCM concentration of 104 nM (4-min incubation). A 10-min preincubation with 10 microM HCM results in essentially complete (greater than 95%) inactivation that persists after washing. Low-affinity choline transport in synaptosomes is unaffected by HCM inhibition at all concentrations examined (1-50 microM). Time course experiments indicate that the maximum irreversible inhibition (58%) seen after a 1-min preincubation with 500 nM HCM decreases to 46% inhibition after a 15-min preincubation; however, analysis of variance reveals that this difference is not significant. HCM inhibition of acetylcholine release from myenteric plexus-longitudinal muscle preparations persists for at least 2 h after removal of drug from the incubation bath; this inactivation can be prevented by coincubation with a high choline concentration during treatment with the mustard. In contrast, inhibition produced by the parent compound hemicholinium-3 is largely reversed by washing in both preparations examined. The observed potency and selectivity of HCM suggest its usefulness as a covalent probe for high-affinity choline transport.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylcholine / antagonists & inhibitors
  • Animals
  • Biological Transport / drug effects
  • Brain / metabolism
  • Choline / antagonists & inhibitors*
  • Choline / metabolism
  • Guinea Pigs
  • Hemicholinium 3 / analogs & derivatives*
  • In Vitro Techniques
  • Male
  • Myenteric Plexus / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Synaptosomes / metabolism


  • Hemicholinium 3
  • Choline
  • Acetylcholine