Agricultural, pharmaceutical, and other biologically active substances are emptied or leach into waterways and groundwater, where they can dose-relatedly cause pharmacologic or toxic effects on the resident or depende...Agricultural, pharmaceutical, and other biologically active substances are emptied or leach into waterways and groundwater, where they can dose-relatedly cause pharmacologic or toxic effects on the resident or dependent animal species. Standard methods can be used to evaluate the effects of individual substances, but evaluation of combinations of substances is more difficult. The mathematically rigorous method of isobolographic analysis was coupled with a simple in vivo invertebrate model. Planarians were selected because they are the lowest extant species with a centralized nervous system. Neostigmine bromide and monopotassium phosphate (KH2PO4) were selected as representative of two types of potential pollutants. Neostigmine bromide and KH2PO4 individually produced dose-related lethality over a 60-minute observation period with LD50 values of 122 and 70 mM, respectively. The LD50 value of a 1:1 combination of the two was significantly different (p < 0.05) from the isobolographic line of additivity. We used planarians as a representative fresh-water species and joint-action (‘isobolographic’) analysis to examine possible interaction between pollutants. In the demonstrative example reported here, there was a subadditive interaction between a 1:1 fixed-ratio combination of neostigmine bromide (as a representative acetylcholinesterase inhibitor used in pesticides) and potassium phosphate (used in fertilizers and detergents).展开更多
文摘Agricultural, pharmaceutical, and other biologically active substances are emptied or leach into waterways and groundwater, where they can dose-relatedly cause pharmacologic or toxic effects on the resident or dependent animal species. Standard methods can be used to evaluate the effects of individual substances, but evaluation of combinations of substances is more difficult. The mathematically rigorous method of isobolographic analysis was coupled with a simple in vivo invertebrate model. Planarians were selected because they are the lowest extant species with a centralized nervous system. Neostigmine bromide and monopotassium phosphate (KH2PO4) were selected as representative of two types of potential pollutants. Neostigmine bromide and KH2PO4 individually produced dose-related lethality over a 60-minute observation period with LD50 values of 122 and 70 mM, respectively. The LD50 value of a 1:1 combination of the two was significantly different (p < 0.05) from the isobolographic line of additivity. We used planarians as a representative fresh-water species and joint-action (‘isobolographic’) analysis to examine possible interaction between pollutants. In the demonstrative example reported here, there was a subadditive interaction between a 1:1 fixed-ratio combination of neostigmine bromide (as a representative acetylcholinesterase inhibitor used in pesticides) and potassium phosphate (used in fertilizers and detergents).
