Avoidance learning under delayed shock termination in prenatally x‐irradiated rats

Tamaki, Yoshitaka; Inouye, Minoru

doi:10.1002/dev.420140202

Cited by 9 publications

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References 9 publications

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“…Acute exposure to high doses of radiation in the midfetal period (referred to as day 14 to day 17 of gestation in rats) resulted in the rapid acquisition of shuttle avoidance behavior in rat offspring (Deagle and Furchtgott, 1969;Furchtgott et al, 1970;Furchtgott and Wechkin, 1962;Jensh et al, 1987;Martin, 1970;Tamaki and Inouye, 1979, 1981, 1988Tamaki et al, 1976). While avoidance learning can be affected by a variety of motor and sensory dysfunctions, alternations in reactivity or drive component, and changes in shock sensitivity, Furchtgott et al (1970) have pointed out the importance of the emotional basis of drive.…”

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Avoidance Learning Deficits in Prenatally Gamma‐Ray Irradiated Rats

Tamaki

Hoshino

Kameyama

1989

Congenital Anomalies

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Pregnant female rats of the Fischer344 (F344/Du Crj) strain were exposed to gamma-ray radiation of 1.46Gy on day 15 of gestation (vaginal plug = day 0). When male offspring of control and irradiated dams matured, they were trained with various avoidance conditioning paradigms. In the avoidance acquisition paradigm in which one of the tone-on and lights-off signals was presented with predetermined random sequences, the irradiated group had lower overall rates of active avoidance responding than controls. In the go/no-go (active-passive) discrimination avoidance paradigm after rats learned only active avoidance responses to these two different signals, irradiated rats established stable active avoidance rates under the go (tone-on) signal, while they decreased gradually the rate of passive avoidance responding to the no-go (lights-off) signal as the amount of discrimination training increased. In the standard avoidance acquisition paradigm in which only the lights-off signal was used, the irradiated group also was inferior in active avoidance learning to controls. However, the irradiated group showed a high level of anticipatory responding, which was maintained in avoidance conditioning paradigms even though no shock-avoidance contingency was operating. These results indicated that poor associative ability for the warning signal and the shock might result in the active avoidance learning deficits in irradiated rats, and that active responding was more persistent and passive responding declined due to response excitation within a shock paradigm over the subsequent further training.

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confidence: 99%

Avoidance Learning Deficits in Prenatally Gamma‐Ray Irradiated Rats

Tamaki

Hoshino

Kameyama

1989

Congenital Anomalies

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Studies of the effect of 0.4‐Gy and 0.6‐Gy prenatal X‐irradiation on postnatal adult behavior in the Wistar rat

1987

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Thirty-four pregnant Wistar rats were X-irradiated on the 9th or 17th day of gestation at a dosage level 0.4 Gy or 0.6 Gy or were sham-irradiated. All mothers were allowed to deliver their offspring, and litters were limited to a maximum of eight on day 2. On day 30, 224 offspring were weaned and raised until 60 days of age, at which time testing began. Each rat randomly received, in random order, three of the following six behavioral tests: Water T-maze, Conditioned Avoidance Response, Forelimb Hanging, Activity Wheel, Swimming, and Open Field. There were no statistically significant differences between the irradiated and control groups for maternal weight or weight gain or mean litter size, although the litter size of the 17th day 0.6-Gy group was slightly lower. Among offspring irradiated with 0.6 Gy on the 17th day, 3-day-old neonates' weights were significantly reduced. Offspring irradiated on the 17th day with 0.6 Gy exhibited higher Conditioned Avoidance Response 5th-day and retest avoidance scores than did the controls. There were also significant sex differences in responses within the irradiated and control groups for several tests, which were unrelated to radiation exposure. The results of this study indicate that low-level X-irradiation during the fetal period of rat gestation results in neonatal growth retardation and subtle behavioral alterations that may be manifested in adult life. Growth retardation may be the most sensitive indicator of subtle effects that result from low-level prenatal exposure to X-rays.

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Effects of prenatal X‐irradiation on the 14th–18th days of gestation on postnatal growth and development in the rat

Jensh

Brent

1988

Teratology

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Thirty-nine pregnant adult Wistar strain rats were randomly assigned to one of three exposure groups: 0, 0.75, or 1.50 Gy X-radiation total exposure. Animals were exposed from the 14th to the 18th days of gestation at 0, 0.15, or 0.30 Gy per day. At term, 15 rats were killed and morphologic analyses were completed. Twenty-four rats were allowed to deliver their offspring. On the first day of postnatal life, litters were reduced to a maximum of eight pups per litter, with equal numbers of male and female offspring wherever possible. A total of 187 pups were observed for the age of acquisition of five reflexes (air righting, surface righting, visual placing, negative geotaxis, auditory startle) and the appearance of four physiologic markers (pinna detachment, eye opening, vaginal opening, testes descent). There was significant dose-related weight reduction in term fetuses and offspring throughout the 86-day postnatal period. Postnatal growth rate (g gained/day) was unaffected. Adult offspring brain and gonadal weight and organ weight:body weight ratios were reduced. Using the PAC50 methodology, dose-related alterations occurred in the acquisition of several reflexes. All physiologic markers exhibited a dose-related delay in appearance. These results indicate that fractionated exposure to X-radiation during the fetal period in the rat results in dose-dependent alterations in postnatal growth and physiologic development. These studies are important for our understanding of the long-range effects of prenatal exposure to ionizing radiation late in gestation.

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Avoidance learning under delayed shock termination in prenatally x‐irradiated rats

Cited by 9 publications

References 9 publications

Avoidance Learning Deficits in Prenatally Gamma‐Ray Irradiated Rats

Avoidance Learning Deficits in Prenatally Gamma‐Ray Irradiated Rats

Studies of the effect of 0.4‐Gy and 0.6‐Gy prenatal X‐irradiation on postnatal adult behavior in the Wistar rat

Effects of prenatal X‐irradiation on the 14th–18th days of gestation on postnatal growth and development in the rat

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