Toxicology and Mode of Action of Pyrethroid Insecticides

Soderlund, David M.

doi:10.1016/b978-0-12-374367-1.00077-x

Cited by 63 publications

(77 citation statements)

References 120 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These currents are also typical of the effects of Type I compounds on voltage-clamped sodium currents in neuronal preparations (Soderlund, 1995; Soderlund, 2010b). A high concentration of S -bioallethrin produced only weak resting modification of Na v 1.6 channels, and the extent of modification was not enhanced by repeated depolarization.…”

Section: Discussionmentioning

confidence: 93%

“…The three compounds selected for this study exemplify the diversity of acute neurotoxic effects caused by pyrethroids (Soderlund et al , 2002; Soderlund, 2010b). S -Bioallethrin, an analog of the natural insecticide constituent pyrethrin I, is a member of the Type I structural class and produces the T intoxication syndrome in rodents.…”

Section: Discussionmentioning

confidence: 99%

“…Deltamethrin produced slowly-decaying sodium tail currents with time constants approximately 10-fold greater than those caused by S -bioallethrin, an effect typical of Type II compounds (Soderlund, 1995; Soderlund, 2010b). Resting modification of Na v 1.6 channels by deltamethrin was barely detectable, but the extent of modification was increased substantially by the application of trains of short depolarizing prepulses.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Divergent actions of the pyrethroid insecticides S-bioallethrin, tefluthrin, and deltamethrin on rat Nav1.6 sodium channels

Tan

Soderlund

2010

Toxicology and Applied Pharmacology

Self Cite

View full text Add to dashboard Cite

We expressed rat Nav1.6 sodium channels in combination with the rat β1 and β2 auxiliary subunits in Xenopus laevis oocytes and evaluated the effects of the pyrethroid insecticides S-bioallethrin, deltamethrin and tefluthrin on expressed sodium currents using the two-electrode voltage clamp technique. S-Bioallethrin, a Type I structure, produced transient modification evident in the induction of rapidly-decaying sodium tail currents, weak resting modification (5.7% modification at 100 μM), and no further enhancement of modification upon repetitive activation by high-frequency trains of depolarizing pulses. By contrast deltamethrin, a Type II structure, produced sodium tail currents that were ~9-fold more persistent than those caused by S-bioallethrin, barely detectable resting modification (2.5% modification at 100 μM), and 3.7-fold enhancement of modification upon repetitive activation. Tefluthrin, a Type I structure with high mammalian toxicity, exhibited properties intermediate between S-bioallethrin and deltamethrin: intermediate tail current decay kinetics, much greater resting modification (14.1% at 100 μM), and 2.8-fold enhancement of resting modification upon repetitive activation. Comparison of concentration–effect data showed that repetitive depolarization increased the potency of tefluthrin ~15-fold and that tefluthrin was ~10-fold more potent than deltamethrin as a use-dependent modifier of Nav1.6 sodium channels. Concentration–effect data from parallel experiments with the rat Nav1.2 sodium channel co-expressed with the rat β1 and β2 subunits in oocytes showed that the Nav1.6 isoform was at least 15-fold more sensitive to tefluthrin and deltamethrin than the Nav1.2 isoform. These results implicate sodium channels containing the Nav1.6 isoform as potential targets for the central neurotoxic effects of pyrethroids.

show abstract

Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Divergent actions of the pyrethroid insecticides S-bioallethrin, tefluthrin, and deltamethrin on rat Nav1.6 sodium channels

Tan

Soderlund

2010

Toxicology and Applied Pharmacology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Both tefluthrin and deltamethrin produced a persistent “late” current during membrane depolarization and a sodium tail current following membrane repolarization. The induction of late and tail currents is a hallmark of pyrethroid action on sodium channels in both native neurons and heterologous expression systems (Soderlund et al , 2002; Soderlund, 2010b). The greater persistence of deltamethrin-induced late and tail currents is also typical of results obtained in other experimental systems with deltamethrin and other Type II pyrethroid structures (Soderlund et al , 2002).…”

Section: Discussionmentioning

confidence: 99%

Effects of the β1 auxiliary subunit on modification of Rat Nav1.6 sodium channels expressed in HEK293 cells by the pyrethroid insecticides tefluthrin and deltamethrin

Soderlund

2016

Toxicology and Applied Pharmacology

Self Cite

View full text Add to dashboard Cite

We expressed rat Nav1.6 sodium channels with or without the rat β1 subunit in human embryonic kidney (HEK293) cells and evaluated the effects of the pyrethroid insecticides tefluthrin and deltamethrin on whole-cell sodium currents. In assays with the Nav1.6 α subunit alone, both pyrethroids prolonged channel inactivation and deactivation and shifted the voltage dependence of channel activation and steady-state inactivation toward hyperpolarization. Maximal shifts in activation were ~18 mV for tefluthrin and ~24 mV for deltamethrin. These compounds also caused hyperpolarizing shifts of ~10–14 mV in the voltage dependence of steady-state inactivation and increased in the fraction of sodium current that was resistant to inactivation. The effects of pyrethroids on the voltage-dependent gating greatly increased the size of sodium window currents compared to unmodified channels; modified channels exhibited increased probability of spontaneous opening at membrane potentials more negative than the normal threshold for channel activation and incomplete channel inactivation. Coexpression of Nav1.6 with the β1 subunit had no effect on the kinetic behavior of pyrethroid-modified channels but had divergent effects on the voltage-dependent gating of tefluthrin- or deltamethrin-modified channels, increasing the size of tefluthrin-induced window currents but decreasing the size of corresponding deltamethrin-induced currents. Unexpectedly, the β1 subunit did not confer sensitivity to use-dependent channel modification by either tefluthrin or deltamethrin. We conclude from these results that functional reconstitution of channels in vitro requires careful attention to the subunit composition of channel complexes to ensure that channels in vitro are faithful functional and pharmacological models of channels in neurons.

show abstract

“…The toxic signs of pyrethroid insecticides set in by acting on the nervous system. Although their principal target is the voltage-gated sodium channel, recent studies propose that they target other channel and receptor systems in the neuronal tissues as well, such as calcium, chloride channels, GABA (γ-aminobutyric acid) and benzodiazepine receptors (4)(5)(6). Several studies have been conducted on the mechanisms that unveil in the neurotoxicity of pyrethroids.…”

mentioning

confidence: 99%

Biological Significance of the Overexpression of HSP70 and Alpha B-Crystallin in Rat Substantia Nigra Exposed to Different Doses of Permethrin

Güvenç

Kabak

Atmaca

et al. 2013

Archives of Industrial Hygiene and Toxicology

View full text Add to dashboard Cite

The aim of this study was to investigate the possible role of the Heat Shock Protein 70 (HSP70) and Alpha B-crystallin (αBC) in the substantia nigra of rats exposed to permethrin at different doses on the apoptotic cell status. The orogastric gavage method was used to administer the different doses of permethrin (75 mg kg -1 in Group I, 150 mg kg -1 in group II, 300 mg kg -1 in group III) to the rats. Using the Western blot test, all the permethrin-treated groups showed a dose-dependent increase in the expression of HSP70 and αBC when compared to the control group. TUNEL positive apoptotic cells were not detected in the dopaminergic neurons of the substantia nigra after treatment with permethrin; however, upon immunofl uorescent staining, intense positive reactions for HSP70 and αBC were observed in all of the treated groups. No immunopositive cells were detected in the tissue sections of the control group. These results suggest that the different administered doses of permethrin did not cause apoptotic cell death in the substantia nigra dopaminergic neurons; however, they did induce an increase in HSP70 and αBC expression. Thus, it appears that HSP70 and αBC could play a neuroprotective role in permethrin-induced neurotoxicity.

show abstract

Toxicology and Mode of Action of Pyrethroid Insecticides

Cited by 63 publications

References 120 publications

Divergent actions of the pyrethroid insecticides S-bioallethrin, tefluthrin, and deltamethrin on rat Nav1.6 sodium channels

Divergent actions of the pyrethroid insecticides S-bioallethrin, tefluthrin, and deltamethrin on rat Nav1.6 sodium channels

Effects of the β1 auxiliary subunit on modification of Rat Nav1.6 sodium channels expressed in HEK293 cells by the pyrethroid insecticides tefluthrin and deltamethrin

Biological Significance of the Overexpression of HSP70 and Alpha B-Crystallin in Rat Substantia Nigra Exposed to Different Doses of Permethrin

Contact Info

Product

Resources

About