Influence of pinacolyl dimethylphosphinate on soman storage in rats

Atropinized rats pretreated with pinacolyl dimethylphosphinate (PDP) or saline were intoxicated with 6 X LD50 soman and, after 30 and 60 min, the absolute amounts of soman in diaphragms and lungs were measured gas chromatographically. The absolute amounts of free soman in both types of tissues were similar and were decreased after 60 min intoxication compared with the 30 min intoxication period. Pretreatment of rats with PDP reduced the amount of soman in the tissues by 63-78%. Incubation of isolated diaphragms and lungs with sodium fluoride (2.5 mM) increased the amount of free soman in these tissues by 2.6 X 10(3) and 16 X 10(3)%, respectively. An assay to study the binding of tritiated PDP was developed. Although this assay was suitable to study the binding of tritiated quinuclidinyl benzilate to rat brain, no binding between tritiated PDP and diaphragm or brain tissue could be detected. It was concluded that PDP may counteract soman storage by another mechanism than occupation of binding sites.