Effects of parental morphine addiction on long term potentiation of the perforant path to dentate gyrus in rat offsprings

Background: Evidences show that parental morphine addiction impairs CNS development, learning and memory in offsprings. Since long term potentiation (LTP) is a cellular mechanism of learning and memory, in this study the effect of parental morphine addiction on LTP induction in dentate gyrus by high frequency stimulation of perforant path was assessed. Materials and methods: In this experimental study 40 female and 16 male rats (120-140 days old) were addicted by oral administration (32mg/kg, twice daily) of morphine for 5 days. Then male rats were placed with female in 5 groups: 1-test 1 group: addicted female rats (n=20) with non addicted male rats (n=8). 2- test 2 group: non addicted female rats (n=20) with addicted male rats (n=8). 3-test 3 group: addicted female rats (n=20) with addicted male rats (n=8). 4-sham control 1: female received dextrose 5% (n=20) with non addicted male rats (n=8). 5- sham control 2: male received dextrose 5% (n=8) with non addicted female rats (n=20. In pubert offsprings, LTP were induced in dentate gyrus by high frequency stimulation (HFS) of perforant path. The magnitude of potentiation was evaluated as percentage change in population spike (PS) amplitude or excitatory post synaptic potential slope (EPSP) at 5, 30, 60 and 120 minutes after HFS. All values were taken as the mean ±SE. Data were analyzed by two way ANOVA. Results: Amplitude of population spike (PS) and slope of excitatory post synaptic potential(EPSP) 60 and 120 minutes after HFS in offsprings of test 1 and test 2 was less than sham controls (p<0.01). There were no difference between test 1 and test 2 and male and female rat offsprings in PS amplitude and EPSP slope. Conclusion: The results suggest that parental morphine addiction may cause learning deficiency through reduction of LTP in dentate gyrus. So, the side effects of parental morphine addiction in offsprings must be considered.