Potent block of Cx36 and Cx50 gap junction channels by mefloquine

Scott J. Cruikshank, Matthew Hopperstad, Meg Younger, Barry W. Connors, David C. Spray, Miduturu Srinivas

Research output: Contribution to journalArticle

239 Citations (Scopus)

Abstract

Recently, great interest has been shown in understanding the functional roles of specific gap junction proteins (connexins) in brain, lens, retina, and elsewhere. Some progress has been made by studying knockout mice with targeted connexin deletions. For example, such studies have implicated the gap junction protein Cx36 in synchronizing rhythmic activity of neurons in several brain regions. Although knockout strategies are informative, they can be problematic, because compensatory changes sometimes occur during development. Therefore, it would be extremely useful to have pharmacological agents that block specific connexins, without major effects on other gap junctions or membrane channels. We show that mefloquine, an antimalarial drug, is one such agent. It blocked Cx36 channels, expressed in transfected N2A neuroblastoma cells, at low concentrations (IC50 ≈ 300 nM). Mefloquine also blocked channels formed by the lens gap junction protein, Cx50 (IC50 ≈ 1.1 μM). However, other gap junctions (e.g., Cx43, Cx32, and Cx26) were only affected at concentrations 10- to 100-fold higher. To further examine the utility and specificity of this compound, we characterized its effects in acute brain slices. Mefloquine, at 25 μM, blocked gap junctional coupling between interneurons in neocortical slices, with minimal nonspecific actions. At this concentration, the only major side effect was an increase in spontaneous synaptic activity. Mefloquine (25 μM) caused no significant change in evoked excitatory or inhibitory postsynaptic potentials, and intrinsic cellular properties were also mostly unaffected. Thus, mefloquine is expected to be a useful tool to study the functional roles of Cx36 and Cx50.

Original languageEnglish (US)
Pages (from-to)12364-12369
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume101
Issue number33
DOIs
StatePublished - Aug 17 2004

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Mefloquine
Connexins
Gap Junctions
Inhibitory Concentration 50
Brain
Inhibitory Postsynaptic Potentials
Connexin 43
Crystallins
Excitatory Postsynaptic Potentials
Antimalarials
Interneurons
Neuroblastoma
Ion Channels
Knockout Mice
Lenses
Retina
Pharmacology
Neurons

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

Potent block of Cx36 and Cx50 gap junction channels by mefloquine. / Cruikshank, Scott J.; Hopperstad, Matthew; Younger, Meg; Connors, Barry W.; Spray, David C.; Srinivas, Miduturu.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 101, No. 33, 17.08.2004, p. 12364-12369.

Research output: Contribution to journalArticle

Cruikshank, Scott J. ; Hopperstad, Matthew ; Younger, Meg ; Connors, Barry W. ; Spray, David C. ; Srinivas, Miduturu. / Potent block of Cx36 and Cx50 gap junction channels by mefloquine. In: Proceedings of the National Academy of Sciences of the United States of America. 2004 ; Vol. 101, No. 33. pp. 12364-12369.
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