Abstract
The effects of chronic daily injections of diisopropylfluorophosphate (DFP) and of subsequent acute challenges with scopolamine, methyl scopolamine, and alpha methyl-p-tyrosine (α-mpt) on the drinking behavior of albino rats have been observed. No measurable changes in behavior were noted with the lowest dose of DFP (0.2 mg/kg), while the highest dose (1.0 mg/kg) was found to exceed the LD 50 (0.56 mg/kg/day) for the present regimen of administration. Animals receiving the intermediate doses of DFP (0.4, 0.5 mg/kg) were affected after a latency of approximately 6 days, but their drinking behavior returned to normal during the chronic treatment period, i.e., tolerance developed. Results of subsequent acute challenges with scopolamine indicated that the neurochemical processes underlying the behavior of all DFP-treated subjects were similar, regardless of whether or not the treatment resulted in initial behavioral deficits, and that these processes were different from those underlying the behavior of normal control subjects. Challenges with methyl scopolamine produced effects on the drinking behavior which did not differ for control and DFP-treated animals, while challenges with α-mpt were without significant effects.
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This research was supported by Grant MH 18788 from the National Institute of Mental Health to Roger W. Russell.
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Chippendale, T.J., Zawolkow, G.A., Russell, R.W. et al. Tolerance to low acetylcholinesterase levels: Modification of behavior without acute behavioral change. Psychopharmacologia 26, 127–139 (1972). https://doi.org/10.1007/BF00422099
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DOI: https://doi.org/10.1007/BF00422099