Exposure To Caffeine During Pregnancy And Altered Learning And Memory In The Rat Offspring

Part 1 The effect of prenatal caffeine exposure on fetal development and adult offspring bodyweightObjective: To determine the effect of prenatal caffeine exposure on fetal development and adult offspring bodyweight.Methods: Saline(control group:16 mothers) or caffeine(caffeine group: 16 mothers; 20 mg/kg/per dose; twice a day) was subcutaneously injected daily to pregnant mothers from GD 3.5 to 19.5. On GD20.5, after cesarean section delivery, fetal brain and body weight was measured(the litter size of each pregnant rat was 9 to 13, eight mothers each group). Natural delivery was allowed for other pregnant rats. The brain and body weight was measured when offspring was anesthetized with sodium pentobarbital on 14 th day(n=50/group). The other offspring were studied at 5-mont-old.Results: There were significant changes in fetal body and the ratio of brain weight/body weight following exposure to caffeine, whereas no significant difference in brain weight was found between two groups. And brain and body weight of offspring exposed to caffeine at 14-day-old were significantly lower than that of control as the ratio of brain weight /body weight was not significantly different.Conclusion: Prenatal caffeine exposure may effect development of brain and lead to intrauterine growth restriction. Part 2 The effect of prenatal caffeine exposure on learning and memeory in adult offspring ratObjective: To determine the effects of caffeine during pregnancy on learning and memory in the adult offspring rat.Methods: the adult offspring of two groups was divided to four subgroups by gender. And the behavior development were tested with water maze.Result: The escape latency was significantly increased in the male offspring from day1 to day 5 compared with the control, and the path length was significantly increased at day 1 to day 3. The femal offspring also showed longer escape latency in the test duration and longer path length at first 3 days and the last day. In the probe trial(retention test), the number of target quadrant approaches in the male offspring was significantly less than that of the control. However the nuanmber of target approaches showed no significant difference. While the female offspring showed both less number of target and target quadrant approaches on seventh day after withdrawing platform.Conclusion: Maternal caffeine during gestation influenced the ability of learning and memory in the same-sex adult offspring.Part 3 The effect of prenatal caffeine exposure on adenosine receptors and PKA pathway of hippopotamusObjective: To determine the effects of caffeine during pregnancy on adenosine receptors and downstream PKA pathway.Methods: the hippopotamus of adult offspring of two groups are geted. Real-time Quantitative PCR was used to detect the expression of m RNA of CREB,BDNF and Tr KB. The proteins of A1 R,A2a R,c AMP,PKA-Cα,PKA-Cβ,p-CREB,BDNF and Tr KB were measured by ELISA.Result: 1) Prenatal caffeine significantly decreased the expression of CREB m RNA in fetal and adult hippopotamus compare to the control. As the expression of BDNF m RNA was significantly decreased in caffeine fetal and adult hippopotamus. In addition,there was significantly increase of Tr KB m RNA in caffeine adult hippopotamus but significantly decrease in that of fetal; 2) There was significantly difference of A1 R, PKA-Cβ subunit and BDNF in fetal and adult hippopotamus of caffeine offspring. But no significantly difference of A2 a R, c AMP, PKA-Cα subunits and p-CREB was found in fetal and adult hippopotamus between two groups. For caffeine fetal hippopotamus,there was significantly decrease in the expression of Tr KB protein, while significantly higher protein expression of Tr KB in caffeine adult hippopotamus.Conclusion: Prenatal caffeine exposure may affect A1 R expression and c AMP-PKA pathway, and these effect may continue to adulthood. The downstream of c AMP-PKA pathway is crucial to learning and memory.