Effects of repeated kainic acid seizures in the immature rat: a decrease in seizure intensity and long-term consequences.
摘要
Long-term cognitive impairment occurs in both humans and laboratory animals following a single prolonged seizure (e.g. status epilepticus). However, the effects of multiple seizures on the developing brain have not been investigated in as much detail. Here, we studied the acute electrographical and behavioral effects of repeated kainic acid (KA) seizures in immature rats, and then tested their learning and memory as adults. Immature rats were implanted with electrodes in the dorsal hippocampus on postnatal day (P) 16, then received KA injections (10 mg/kg) on P20, 22, 24, and 26. Following the first KA injection (P20), all rats developed severe behavioral and electrographic seizures. Subsequent KA injections (P22, 24, 26) caused less intense seizures. To test the effects of multiple seizures on later cognitive performance, another set of rats was trained in the water maze from P16-19, then injected with KA as above. The rats were retested in the water maze at P60. KA treatment had no effect on the latency to find the platform. These results suggest that seizure intensity progressively decreases with serial injections of KA in immature rats. In addition, repeated KA seizures during development do not lead to a deficit in spatial learning.