Pick C G, Yanai J
Department of Anatomy and Embryology, The Hebrew University-Hadassah Medical School, Box 1172, 91010 Jerusalem, Israel.
Int J Dev Neurosci. 1984;2(3):223-8. doi: 10.1016/0736-5748(84)90016-9.
Spontaneous alternation behavior is related to the integrity of the hippocampus. Our earlier studies demonstrated hippocampal deficits after early phenobarbital (PhB) exposure. In the present study, we examined spontaneous alternation of mice who had been exposed to PhB prenatally or neonatally. Prenatal PhB was administered transplacentally: pregnant females were fed 3 g PhB/kg milled food on gestation days 9-18. Neonates were treated directly with daily injections of 50 mg PhB/kg on postnatal days 2-22. The animals were tested for spontaneous alternation in a T maze at the ages of 22, 28, 35 and 42 days. The test was conducted at each age for two consecutive days. A maximum of four alternations were allowed on the first day, and one alternation on the second day. Animals treated neonatally had reductions in alternation from the control group for every age group. Looking at the mean of the four trials on the first day there was a reduction of 35% at age 22 (P < 0.001), 8% at age 28, 21% at age 35 (P < 0.05) and 36% at age 42 (P < 0.02). On the second day the respective reductions were 32, 19, 24 and 36% (P < 0.05). The differences in alternation between animals treated with PhB prenatally and the control group were too small to reach statistical significance. Subsequently a more sensitive test, delayed spontaneous alternation (30 s), was applied to an additional group of animals at age 42 which had been prenatally exposed to PhB: 31% reduction from the control group was found on day 1 (P < 0.001), and 34% on day 2 (P < 0.02). The greater differences after neonatal as opposed to prenatal administration could be related to the more extensive hippocampal damage that was found in adults after neonatal treatment.
自发交替行为与海马体的完整性有关。我们早期的研究表明，早期接触苯巴比妥（PhB）后会出现海马体缺陷。在本研究中，我们检测了产前或新生儿期接触过PhB的小鼠的自发交替行为。产前PhB通过胎盘给药：怀孕的雌性小鼠在妊娠第9至18天被喂食含3 g PhB/kg的研磨食物。新生小鼠在出生后第2至22天每天直接注射50 mg PhB/kg进行治疗。在22、28、35和42日龄时，对动物进行T迷宫自发交替测试。每个年龄段连续两天进行测试。第一天最多允许四次交替，第二天允许一次交替。在每个年龄组中，新生儿期接受治疗的动物与对照组相比，交替次数减少。观察第一天四次试验的平均值，22日龄时减少了35%（P < 0.001），28日龄时减少了8%，35日龄时减少了21%（P < 0.05），42日龄时减少了36%（P < 0.02）。第二天相应的减少率分别为32%、19%、24%和36%（P < 0.05）。产前接触PhB的动物与对照组之间的交替差异太小，无统计学意义。随后，对另一组42日龄产前接触过PhB的动物进行了更敏感的测试，即延迟自发交替（30秒）：第1天发现比对照组减少了31%（P < 0.001），第2天减少了34%（P < 0.02）。与产前给药相比，新生儿期给药后差异更大，这可能与新生儿期治疗后成年动物海马体损伤更广泛有关。
