Action of deltamethrin on N-type (Cav2.2) voltage-sensitive calcium channels in rat brain |
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| Authors: | Steven B Symington |
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| Institution: | a Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA 01003, USA
b Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003, USA |
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| Abstract: | Isolated presynaptic nerve terminals prepared from whole rat brain were used to evaluate the action of deltamethrin on voltage-sensitive calcium channels by measuring calcium influx and endogenous glutamate release. Deltamethrin-enhanced K+-stimulated calcium influx and subsequent Ca2+-dependent glutamate release. The effect of deltamethrin was concentration-dependent, stereospecific, blocked by ω-conotoxin MVIIC but unaltered in the presence of tetrodotoxin. These results suggest that N-type voltage-sensitive calcium channels are a site of action at the presynaptic nerve terminal. Electrophysiological studies were carried out using rat brain Cav2.2 and β3 subunits coexpressed in Xenopus oocytes to validate such action. Deltamethrin reduced barium peak current in a concentraion-dependent and stereospecific manner, increased the rate of activation, and prolonged the inactivation rate of this channel. These experiments support the conclusion that N-type voltage-sensitive calcium channel operation is altered by deltamethrin. |
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| Keywords: | Calcium channel Deltamethrin Electrophysiology Neurotransmission Presynaptic nerve terminal Pyrethroids Rat brain Synaptosomes Xenopus laevis |
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