Format

Send to

Choose Destination
See comment in PubMed Commons below
Mar Drugs. 2010 Mar 19;8(3):741-62. doi: 10.3390/md8030741.

Effects of tetrodotoxin on the mammalian cardiovascular system.

Author information

  • 1Institute of Physiology II, Friedrich Schiller University, Kollegiengasse 9, 07743 Jena, Germany. thomas.zimmer@mti.uni-jena.de

Abstract

The human genome encodes nine functional voltage-gated Na+ channels. Three of them, namely Na(v)1.5, Na(v)1.8, and Na(v)1.9, are resistant to nanomolar concentrations of tetrodotoxin (TTX; IC(50) > or = 1 microM). The other isoforms, which are predominantly expressed in the skeletal muscle and nervous system, are highly sensitive to TTX (IC(50) approximately 10 nM). During the last two decades, it has become evident that in addition to the major cardiac isoform Na(v)1.5, several of those TTX sensitive isoforms are expressed in the mammalian heart. Whereas immunohistochemical and electrophysiological methods demonstrated functional expression in various heart regions, the physiological importance of those isoforms for cardiac excitation in higher mammals is still debated. This review summarizes our knowledge on the systemic cardiovascular effects of TTX in animals and humans, with a special focus on cardiac excitation and performance at lower concentrations of this marine drug. Altogether, these data strongly suggest that TTX sensitive Na+ channels, detected more recently in various heart tissues, are not involved in excitation phenomena in the healthy adult heart of higher mammals.

KEYWORDS:

Na+ channel; TTX poisoning; TTX sensitivity; cardiac conduction

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for PubMed Central
    Loading ...
    Write to the Help Desk