Progressive behavioral changes during the maturation of rats with early radiation-induced hypoplasia of fascia dentata granule cells
- Armed Forces Radiobiology Research Institute, Bethesda, MD (USA)
Localized exposure of the neonatal rat brain to X-rays produces neuronal hypoplasia specific to the granule cell layer of the hippocampal dentate gyrus. This brain damage causes locomotor hyperactivity, slowed acquisition of passive avoidance tasks and long bouts of spontaneous turning (without reversals) in a bowl apparatus. Here we report how these behavioral deficits change as a function of subject aging and behavioral test replications. Portions of the neonatal rat cerebral hemispheres were X-irradiated in order to selectively damage the granule cells of the dentate gyrus. The brains of experimental animals received a fractionated dose of X rays (13 Gy total) over postnatal days 1 to 16 and control animals were sham-irradiated. Rats between the ages of 71-462 days were tested 3 separate times on each of the following 3 behavioral tests: (1) spontaneous locomotion, (2) passive avoidance acquisition, and (3) spontaneous circling in a large plastic hemisphere. Rats with radiation-induced damage to the fascia dentata exhibited long bouts of slow turns without reversals. Once they began, irradiated subjects perseverated in turning to an extent significantly greater than sham-irradiated control subjects. This irradiation effect was significant during all test series. Moreover, in time, spontaneous perseverative turning was significantly potentiated in rats with hippocampal damage but increased only slightly in controls. Early radiation exposure produced locomotor hyperactivity in young rats. While activity levels of controls remained fairly stable throughout the course of the experiment, the hyperactivity of the irradiated animals decreased significantly as they matured.
- OSTI ID:
- 5183558
- Journal Information:
- Neurotoxicology and Teratology; (USA), Vol. 11:4; ISSN 0892-0362
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HIPPOCAMPUS
BIOLOGICAL RADIATION EFFECTS
NERVOUS SYSTEM DISEASES
RADIOINDUCTION
AGE DEPENDENCE
BEHAVIOR
LEARNING
NEONATES
PREGNANCY
RADIATION INJURIES
RATS
X RADIATION
ANIMALS
BIOLOGICAL EFFECTS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DISEASES
ELECTROMAGNETIC RADIATION
INJURIES
IONIZING RADIATIONS
MAMMALS
NERVOUS SYSTEM
ORGANS
RADIATION EFFECTS
RADIATIONS
RODENTS
VERTEBRATES
560152* - Radiation Effects on Animals- Animals