ABSTRACT
A considerable data base has been developed on the intraspecies thermoregulatory sensitivity to anti-ChE agents in the rat and mouse. Many studies have focused on the hypothermic response to acute exposure to organophosphate agents. Diisopropyl fluorophosphate (DFP) is an organophosphate that elicits a marked decrease in core temperature that peaks at 4 to 6 h after a subcutaneous injection in the rat (see Chapter 3). In a study using colonic probes, it was shown that the inbred Fischer 344 (F344) strain was relatively insensitive to the acute effects of DFP when compared to the outbred Long-Evans (LE) and Sprague-Dawley (SD) strains (Gordon and MacPhail, 1993). A DFP dose of 1.5 mg/kg led to a 0.3°C decrease in core temperature of the F344 strain but a 0.5 and 1.3°C decrease in the LE and SD strains, respectively, when measured 90 min after injection. Motor activity was reduced in proportion to the reduction in core temperature in all three strains, but strain differences were more apparent in deficiencies in horizontal activity (i.e., movement within the chamber) than with vertical activity (i.e., rearing movement).
