The effects of the organophosphorous insecticides Dursban™ and Lorsban™ on the ciliated epithelium of the frog palate In Vitro

Abstract

The ciliotoxic potential of the organophosphorous insecticides Dursban and Lorsban, their active ingredient, chlorpyrifos, and their carrier ingredients (Blanks) were assessed. Since chlorpyrifos inhibits acetylcholinesterase, the acetylcholine-innervated ciliated epithelial cultures of frog palate were used as the model. All compounds caused a decrease in frequency of ciliary beat overtime. EC50 values followed the same order as the time to inhibition. The orders were Lorsban > Dursban > chlorpyrifos, and Lorsban > Dursban approximately Lorsban Blank > Dursban Blank. Stimulation of ciliary beating occurred immediately after exposure to all compounds, followed by inhibition. Dursban, Lorsban, and both Blanks elicited stimulatory effects in the presence of atropine. Atropine only blocked the initial stimulatory response with chlorpyrifos. In addition to chlorpyrifos, some component(s) of the inert ingredients were initially stimulatory but ultimately inhibitory to ciliary beating in the frog palate model. All compounds caused mitochondrial damage, including swelling, disruption of cristae, and loss of matrix.

Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in U.S. Streams, 1999−2000: A National Reconnaissance

“…Although individual compounds were generally detected at low-levels, total concentrations of the OWCs commonly exceeded 1 µg/L ( Figure 5). In addition, 33 of the 95 target OWCs are known or suspected to exhibit at least weak hormonal activity with the potential to disrupt normal endocrine function (4,7,8,10,12,22,36,37,(48)(49)(50), all of which were detected in at least one stream sample during this study ( Table 1). The maximum total concentration of hormonally active compounds was 57.3 µg/ L. Aquatic species exposed to estrogenic compounds have been shown to alter normal hormonal levels (7,48,51).…”

Unidentified Inert Ingredients in Pesticides: Implications for Human and Environmental Health

“…Because inert ingredients are rarely identified, studies comparing the effects of the active ingredient, the inert ingredients, and the formulation are not common. Such three-way comparisons were performed in six cited studies (Koyama et al 1997; Oakes and Pollack 1999, 2000; Swann et al 1996; Tang and Song 1996; Zeljezic et al 2006); this literature suggests that the situation is complex. In three instances, interactions between active and inert ingredients were important (Oakes and Pollack 2000; Swann et al 1996; Tang and Song 1996); three studies demonstrated that the increased toxicity was primarily due to the inert ingredients (Koyama et al 1997; Oakes and Pollack 1999; Zeljezic et al 2006).…”

“…In a study by Swann et al (1996), two formulations of the insecticide chlorpyrifos were more neurotoxic in vitro to frogs and caused more damage (swelling) to mitochondria than chlorpyrifos alone. Howe et al (2004) found that exposure of Rana pipiens tadpoles to environmentally relevant concentrations of glyphosate formulations reduced size at metamorphosis but increased time to metamorphosis, frequency of tail damage, and frequency of abnormal gonads.…”

Effects of insecticides on a phytotelmata‐breeding amphibian

“…A small portion of the stock solution (2.8 mL) was added to the experimental units containing 247.2 mL of dechlorinated tap water. Although pesticide toxicity may be attributed to the combination of the effects of the active and inert ingredients and the latter may be more toxic than the actual active ingredient , the rationale for the use of the commercial formulation is that this is the formulation applied in the environment. Because inert ingredients were undisclosed, a vehicle control of the inert ingredients alone was not considered.…”