Effects of pyrethroids on neuronal excitability of adult honeybees Apis mellifera

Pyrethroids act on the nervous system as a primary target organ and exert their neurotoxic effects primarily by altering the conductance of sodium channel, leading to hyperexcitation. However, few studies investigated the effects of pyrethroids on neuronal excitability of honeybee brain neurons. In this study, a whole-cell patch-clamp technique was used to record current threshold, the minimum current to induce an action potential, and peak sodium current in the dissociated honeybee brain neurons treated with bifenthrin, deltamethrin and fluvalinate in vitro & in vivo. The study showed that these pyrethroids greatly suppressed the neuronal excitability as revealed by increasing current injected and inhibited the peak sodium current in honeybees. The three pyrethroids also inhibited steady-state inactivation in addition to reduction of sodium peak current.

Pyrethroids suppressed neuronal excitability and inhibited peak sodium current of honeybee brain neurons.Figure optionsDownload as PowerPoint slideResearch highlights
► Pyrethroids bifenthrin but not fluvalinate, deltamethrin changed the laying-eggs behavior in queens.
► Pyrethroids bifenthrin, fluvalinate or deltamethrin greatly suppressed the excitability of adult honeybee brain neurons.
► Pyrethroids bifenthrin, fluvalinate or deltamethrin inhibited the neuronal peak sodium current in honeybees. The three pyrethroids also inhibited steady-state inactivation of sodium current.