Effects of sublethal doses of ionizing radiation on schedule-controlled performance in rats

Technical Report · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5765024

Mele, P C; Franz, C G; Harrison, J R

Male rats responded under a fixed-ratio (FR) 50 or a fixed-interval (FI) 120-sec schedule of milk delivery. Separate groups were acutely exposed to 0.5, 1.5, 4.5, or 0 (FI only) Gray (Gy) of cobalt-60 gamma radiation 3 times at 43-day intervals. All rats received an acute dose of 6.5 Gy 64 days after the last of these exposures. One-half and 1.5 Gy did not alter FR or FI performance significantly. After 4.5 Gy, no observable changes in performance occurred within 1 hr of exposure. Maximal reductions in FR response rates occurred 24 hr after exposure and recovery followed over the subsequent 72 hr. Post-reinforcement pause was increased and running response rate was decreased by 4.5-Gy. Similar effects were found after each 4.5-Gy exposure. In contrast, FI performance (overall response rate, post-reinforcement pause, running response rate, index of curvature) was not altered reliably by 4.5-Gy. Both FR and FI response rates were reduced by 6.5 Gy beginning 24 hr after exposure; FR rates tended to be reduced more than FI rates 24-72 hr after exposure. Response rates under both schedules recovered gradually over 7 weeks. The behavioral effects of 6.5 Gy did not vary as a function of irradiation history. In contrast, irradiation history affected survival in that 4/9 rats previously exposed to 4.5 Gy died during weeks 4-5 after 6.5 Gy, whereas there were no deaths in the rats previously exposed to lower doses. Radiogenic disruption of operant performance was dose-related, reversible, non-cumulative, and dependent on the schedule of reinforcement.

• Research Organization: Armed Forces Radiobiology Research Inst., Bethesda, MD (USA)
• OSTI ID: 5765024
• Report Number(s): AD-A-205814/7/XAB; AFRRI-SR-88-43
• Country of Publication: United States
• Language: English

Related Subjects

560152* -- Radiation Effects on Animals-- Animals
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACUTE EXPOSURE
ANIMALS
BEHAVIOR
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BIOLOGICAL RADIATION EFFECTS
BODY FLUIDS
COBALT 60
COBALT ISOTOPES
DOSE-RESPONSE RELATIONSHIPS
DOSES
ELECTROMAGNETIC RADIATION
FOOD
GAMMA RADIATION
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
IRRADIATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MALES
MAMMALS
MATERIALS
MILK
MINUTES LIVING RADIOISOTOPES
NUCLEI
ODD-ODD NUCLEI
RADIATION DOSES
RADIATION EFFECTS
RADIATIONS
RADIOISOTOPES
RATS
RODENTS
SUBLETHAL IRRADIATION
SURVIVAL TIME
VERTEBRATES
YEARS LIVING RADIOISOT