Electrical activity of osphradial neurons of the greater pond snail Lymnaea stagnalis is modulated by the brominated flame retardant 1,2-dibromo-4-(1,2 dibromoethyl) cyclohexane

Abstract

Objective 1,2-dibromo-4-(1,2 dibromoethyl) cyclohexane (TBECH) is a brominated flame retardant used as a chemical additive in commercial and industrial manufacturing to reduce product flammability. TBECH has previously been shown to be an endocrine disruptor of the gonadal and thyroid axes, however, its neurotoxic effects, including effects on electrical excitability of neurons, are understudied. Therefore, we investigated the potential of TBECH to modulate electrical activity of neurons from the chemosensory osphradial organ of Lymnaea stagnalis using a suction electrode and extracellular recording.Results Application of TBECH caused a variable response in osphradial nerve spike activity, whereby some recordings showed increased action potential firing and some showed decreased firing. This resulted no significant change in mean action potential frequency after TBECH treatment compared to control (n = 6 separate experiments). However, using semi-automated spike sorting analysis to identify individual spike types from each recording revealed that the frequency of some spike types increased and some decreased within each nerve recording, and that TBECH caused significant modulation of activity. These findings indicate that TBECH may represent an acutely neurotoxic environmental contaminant that has potential to interfere with neural signaling in animals.