Pharmacological studies confirm neurotoxic metabolite(s) produced by the bloom-forming Cylindrospermopsis raciborskii in Hungary
Article first published online: 1 DEC 2013
© 2013 Wiley Periodicals, Inc.
Volume 30, Issue 5, pages 501–512, May 2015
How to Cite
Vehovszky, Á., Kovács, A. W., Farkas, A., Győri, J., Szabó, H. and Vasas, G. (2015), Pharmacological studies confirm neurotoxic metabolite(s) produced by the bloom-forming Cylindrospermopsis raciborskii in Hungary. Environ. Toxicol., 30: 501–512. doi: 10.1002/tox.21927
- Issue published online: 24 APR 2015
- Article first published online: 1 DEC 2013
- Manuscript Accepted: 20 NOV 2013
- Manuscript Revised: 19 NOV 2013
- Manuscript Received: 19 AUG 2013
- Hungarian National Research fund (OTKA). Grant Numbers: K63451, K81370, F046493, GVOP-3.2.1., GVOP-TST 3.3.1-05/1-2005-05-0004/3.0.
- Hungarian Academy of Sciences “Megújítás 2012” Balaton monitoring program and TÁMOP- 4.2.2/B-10/1-2010-0024 project
- bloom sample;
- fish mortality;
- Helix pomatia
A rapid cyanobacterial bloom of Cylindrospermopsis raciborskii (3.2 × 104 filaments/mL) was detected early November, 2012, in the Fancsika pond (East Hungary). The strong discoloration of water was accompanied by a substantial fish mortality (even dead cats were seen on the site), raising the possibility of some toxic metabolites in the water produced by the bloom-forming cyanobacteria (C. raciborskii). The potential neuronal targets of the toxic substances in the bloom sample were studied on identified neurons (RPas) in the central nervous system of Helix pomatia. The effects of the crude aqueous extracts of the Fancsika bloom sample (FBS) and the laboratory isolate of C. raciborskii from the pond (FLI) were compared with reference samples: C. raciborskii ACT 9505 (isolated in 1995 from Lake Balaton, Hungary), the cylindrospermopsin producer AQS, and the neurotoxin (anatoxin-a, homoanatoxin-a) producer Oscillatoria sp. (PCC 6506) strains. Electrophysiological tests showed that both FBS and FLI samples as well the ACT 9505 extracts modulate the acetylcholine receptors (AChRs) of the neurons, evoking ACh agonist effects, then inhibiting the ACh-evoked neuronal responses. Dose–response data suggested about the same range of toxicity of FBS and FLI samples (EC50 = 0.397 mg/mL and 0.917 mg/mL, respectively) and ACT 9505 extracts (EC50 = 0.734 mg/mL). The extract of the neurotoxin-producing PCC 6506 strain, however, proved to be the strongest inhibitor of the ACh responses on the same neurons (EC50 = 0.073 mg/mL). The presented results demonstrated an anatoxin-a-like cholinergic inhibitory effects of cyanobacterial extracts (both the environmental FBS sample, and the laboratory isolate, FLI) by some (yet unidentified) toxic components in the matrix of secondary metabolites. Previous pharmacological studies of cyanobacterial samples collected in other locations (Balaton, West Hungary) resulted in similar conclusions; therefore, we cannot exclude that this chemotype of C. raciborskii which produce anatoxin-a like neuroactive substances is more widely distributed in this region. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 501–512, 2015.