Email updates

Keep up to date with the latest news and content from BMC Neuroscience and BioMed Central.

Open Access Research article

Modulation of TTX-sensitive voltage-dependent Na+ channels by β-bungarotoxin in rat cerebellar neurons

Da Guo1, Wei Xiang2, Angela Seebahn2, Cord-Michael Becker2 and Olaf Strauß1*

Author Affiliations

1 Experimental Ophthalmology, Eye Hospital, University Medical Center Regensburg, Franz-Josef-Strauss Allee 11, 93053 Regensburg, Germany

2 Institute of Biochemistry, Emil-Fischer Zentrum, Friedrich-Alexander University Erlangen-Nürnberg, Fahrstraße 17, 91054 Erlangen, Germany

For all author emails, please log on.

BMC Neuroscience 2012, 13:36  doi:10.1186/1471-2202-13-36

Published: 29 March 2012

Abstract

Background

The modulation of voltage-dependent Na+ channels by lipid metabolites such as arachidonic acid or eicosanoids plays a role in physiological functions as well as in degenerative diseases. So far TTX-resistant channels were found mainly to be regulated by lipid metabolites.

Results

We investigated the lipid-dependent modulation of TTX-sensitive (TTX-s) Na+ channels using β-bungarotoxin (β-BuTX, 10 pM), which has an intrinsic phospholipase-A2 activity, and indomethacin (10 μM), which blocks cyclooxygenase activity in primary cerebellar neurons. To investigate TTX-s Na+ channels, whole-currents were measured under K+-free conditions and blocked by 10 nM TTX. The currents resulting from calculating the difference of currents measured in the presence and the absence of TTX were used for further analysis. Application of indomethacin mainly changed the current kinetics but has only minor effects on voltage-dependence. In contrast β-BuTX increased the maximal current amplitude and shifted the voltage-dependent activation towards more negative potentials. The effects of β-BuTX were blocked by indomethacin. Analysis of lipid metabolites which accumulate by treatment with β-BuTX using MALDI-TOF MS showed an increase of cyclooxygenase reaction products in relation to arachidonic acid.

Conclusions

In summary, we conclude that TTX-sensitive Na+ channels can be directly modulated by cyclooxygenase reaction products leading to higher activity at less depolarized potentials and subsequent higher excitability of neurons. Since activation of cyclooxygenase is also involved in pathways leading to apoptotic cells death this could play a role in degenerative diseases of the CNS and highlights a possible protective effect of cyclooxygenase inhibition.