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CONCENTRATION DEPENDENT ACCUMULATION OF [3H]-DELTAMETHRIN IN SODIUM CHANNEL N AV1.2 EXPRESSING XENOPUS LAEVIS OOCYTES.
Citation:
WATKINS, J., C. A. MEACHAM, K. M. CROFTON, AND T. J. SHAFER. CONCENTRATION DEPENDENT ACCUMULATION OF [3H]-DELTAMETHRIN IN SODIUM CHANNEL N AV1.2 EXPRESSING XENOPUS LAEVIS OOCYTES. TOXICOLOGY IN VITRO. Elsevier Science Ltd, New York, NY, 21(8):1672-1677, (2007).
Impact/Purpose:
This manuscript reports data examining the accumulation of the pyrethroid deltamethrin in to oocytes expressing voltage sensitive sodium channels. • The results demonstrate that accumulation of deltamethrin into oocytes expressing sodium channels, a known target of pyrethroids, is less than accumulation of this compound in oocytes lacking sodium channels. • The importance of this study is that it provides a means by which to extrapolate tissue levels of deltamethrin following in vitro exposure in oocytes to in vivo brain tissue levels following deltamethrin intoxication. To support criteria for MYP
Description:
Disruption of neuronal voltage-sensitive sodium channels (VSSCs) by pyrethroid insecticides such as deltamethrin (DLT) has been widely studied using Xenopus laevis oocytes transfected with VSSC. However, the extent of pyrethroid accumulation in VSSC-expressing oocytes is unknown. Therefore, accumulation of [(3)H]-DLT in non-transfected, sham (water)-transfected and VSSC (Na(v)1.2+beta(1))-transfected oocytes after a 1h exposure was measured using liquid scintillation counting. Successful transfection of Na(v)1.2+beta(1) VSSCs in X. laevis oocytes was confirmed by two-electrode voltage-clamp; inward, tetrodotoxin (TTX)-sensitive currents were obtained in 98% of all oocytes examined (n=60 in nine experiments). DLT (1.0 microM) induced tail currents in all VSSC-transfected oocytes; TTX also blocked these DLT-induced tail currents. In 0.1 microM DLT solution, non-transfected oocytes accumulated 0.098+/-0.01 ppm [(3)H]-DLT, sham-transfected oocytes accumulated 0.06+/-0.01 ppm DLT, and VSSC-transfected oocytes accumulated 0.050+/-0.009 ppm DLT. In 1.0 microM DLT solution, non-transfected oocytes accumulated 0.62+/-0.08 ppm DLT, sham-transfected oocytes accumulated 0.60+/-0.09 ppm DLT, and VSSC-transfected oocytes accumulated 0.51+/-0.07 ppm DLT. There was a significant difference in DLT accumulation between VSSC-transfected oocytes and non-transfected controls, where the transfected oocytes consistently had less accumulation. • This manuscript reports data examining the accumulation of the pyrethroid deltamethrin in to oocytes expressing voltage sensitive sodium channels. • The results demonstrate that accumulation of deltamethrin into oocytes expressing sodium channels, a known target of pyrethroids, is less than accumulation of this compound in oocytes lacking sodium channels. • The importance of this study is that it provides a means by which to extrapolate tissue levels of deltamethrin following in vitro exposure in oocytes to in vivo brain tissue levels following deltamethrin intoxication.
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TOXICOL IN VITRO
CONCENTRATION DEPENDENT ACCUMULATION OF [3H]-DELTAMETHRIN IN SODIUM CHANNEL N AV1.2 EXPRESSING XENOPUS LAEVIS OOCYTES.