Effects of a cyanobacterial extract containing anatoxin-a(s) on the cardiac rhythm of Leurolestes circunvagans

Abstract

This work presents the effects of an anatoxin-a(s) containing extract on a cockroach semi-isolated heart preparation and the results supporting the extract's biological activity on acetylcholinesterase (purifi ed from eel). The presence of the toxin in cyanobacterial strains Anabaena spiroides (ITEP-024, ITEP-025 and ITEP-026) isolated from the Tapacurá reservoir in Pernambuco, Brazil, was confi rmed by means of liquid chromatography coupled to an ion-trap mass spectrometer. The anticholinesterase activity was assessed biochemically by the Ellman test and was confi rmed by measuring the cockroach's heart rate. The concentration of the extract containing the tested anatoxina(s) (antx-a(s)) (10, 16 and 100 μg.μL-1) inhibited the eel acetylcholinesterase (AChE) by more than 90%. The cockroach cardiac frequency increased by a maximum of about 20% within 29 min after the addition of 2.5×103 μg of extract containing antx-a(s).g-1 bw (n=9, p<0.05). Our results strongly indicate that antx-a(s) is capable of exerting biological effects on cockroach, indicating that more research might be conducted to determine its role in the environment, especially on insects.