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Daily News Archives
From March 22, 2005

Study Shows Pyrethroids Inhibits Neurologic and Immune System Activity
(Beyond Pesticides, March 22, 2005)
A study on the influence of synthetic pyrethroids and piperonyl butoxide (PBO) on rat brain function concluded that these chemicals had inhibitory impacts on nerve cell and immune cell functioning. The study, "Influence of pyrethroids and piperonyl butoxide on the Ca(2+)-ATPase activity of rat brain synaptosomes and leukocyte membranes," conducted by Diel Grosman, PhD, was published in the February issue of the International Journal Of Pharmacology.

This study tested the effects of pyrethroids alone as well as in combination with PBO, a common ingredient to enhance pesticidal potency. Permethrin had a 20% impact on ATPase activity of leukocyte membranes (immune cells,) but a lesser impact on synaptosomes (neurologic cells.) PBO alone inhibited both nerve and immune cells by10-15%. Although, Esbiol and cyfluthrin did not affect either cells when tested alone, in combination with PBO they inhibited activity up to 40%. The study also concluded that the immune cells were more susceptible to inhibition than the nerve cells.

This data confirms the findings of other research on the impact of synthetic pyrethroids, which includes endocrine disruption and carcinogenic effects. It also sheds more light on the impact of synergistic chemical interactions. For instance, in this case when present alone some pyrethroids had virtually no impact on the cells function, however when in combination with PBO a synergistic interaction took place allowing inhibition of cell activity of up to 40%.

Dr. Grosman’s study confirms pyrethroids can impact the nerve and immune system on the most basic level. This study shows that pyrethroids alone and in synergistic interactions inhibit the enzyme ATPase which allows basic cell processes to take place.

Pyrethroids are commonly used for mosquito control and are found in household insect killers. As an alternative to these toxic products, boric acid is a good, least-toxic general household insecticide that works well to combat ants and roaches. For more information on alternatives to common pest problems, see our alternatives factsheets. For alternatives to pyredthroids for mosquito management, Beyond Pesticides recommends an integrated approach that uses a combination of monitoring, site reduction and larviciding.

Take Action: With the onset of mosquito season encourage your community to stop the spraying and use Integrated Pest Management methods. See our Mosquito and West Nile Virus webpage for information on safe, effective mosquito control. Encourage your community to adopt common-sense moquito control that does not rely on toxic chemicals.