The Effects of Diisopropyl Phosphorofluoridate (DFP) on Inter-Response Time and Circadian Patterns of Lever-Pressing in Rats,
WALTER REED ARMY INST OF RESEARCH WASHINGTON DC
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Rats were injected with saline diisopropyl phosphorofluoridate DFP. Three days later the animals were placed in cages in which they could press a lever to obtain their entire daily ration of food. The time of day at which responses occurred and the time between successive responses were recorded over a six day period to determine the circadian pattern of lever-pressing and the distribution of inter-response times IRTs. The saline injected rats exhibited a normal nocturnal pattern of feeding, while both DFP treated groups exhibited a significantly greater tendency to eat during the day. Analysis of the IRT distributions of the three groups showed a different pattern of results. The saline and 1.0 mgkg DFP groups produced identical IRT distributions, while the 2.6 mgkg groups producted an IRT distribution which was marked by significant increases in the interquartile range and median IRT. Since the 1.0 mgkg dose of DFP produced a circadian disruption but did not affect the IRT distribution, it appears that the disruption of circadian activity by DFP which was reported by Raslear and Kaufman 17 cannot be solely explained by simple changes in the motor response. Reprints.
- Anatomy and Physiology