| PART1 MATERNAL ISOLATION STRESS FOR THE INFLUENCE OF EPILEPSY SUSCEPTIBILITY IN INFANTILE RATSPurpose: To explore the influence of maternal isolation stress on the epilepsy susceptibility of li-pilocapine and amygdala kindling induced-seizures model at infantile ratsMethods: 66 newborn SD rat pups for the experiment( Pregnant rats provide by the Experimental Animal Center of Chongqing Medical University),Our trial was randomly divided into 3 groups(n=66):the normal control group(n=22); maternal separating 15 min group(n=22, (the birth day were designated P0,pups were placed in individual and warmth paper cage containing no bedding and were isolated 15min/day,at the end of maternal isolation period, rats were returned to the dam, Isolations occurred between P2-P15/17day); maternal separating 3 hour group (n=22,with the former method,only separating 3h every day). At P16/18 we performed li-pilocapine and amygdala kindling induced-seizures experiment.Results:Compared with the normal group, during the maternal separating 3 hour group of P2-P15/17 infantile rats, the latency period of li-pilocapine induced-seizures was obvious shorted ( p<0.05 ) ,the convulsive threshold of amygdala kindling and stimulating number need for full kindling were decreased, seizure severity was remarkably increased(p<0.05). However, those of the P2-P15/17 separating 15 min group compared with normal group indicating no significant difference(p>0.05).Conclusion:The stress of early maternal separating 3 hours through shortening the latency period of li-pilocapine induced-seizures; decreasing threshold of amygdala kindling and stimulating number need for full kindling, enhanced the epilepsy susceptibility.PART2 MATERNAL ISOLATION STRESS FOR THE INFLUENCEOF EXPRESSION OF GABAAα1 AND EXCITABILITY OF CA1 PYRAMIDAL NEURON AT HIPPOCAMPUSPurpose: Preliminary exploration of the mechanism of early maternal isolation stress increasing epilepsy susceptibility. Methods: 30 newborn SD rat pups for the experiment ,Our trial was randomly divided into 3 groups: the normal group(n=10); maternal separating 15 min group(n=10 ,the birth day were designated P0,pups were placed in individual and warmth paper cage containing no bedding and were isolated 15min/day,at the end of maternal isolation period, rats were returned to the dam, Isolations occurred between P2-P15day); maternal separating 3 hour group (n=10, with the former method, only separating 3h every day). On the postnatal 16 days,4% paraformaldehyde and saline perfusion of brain, using immunohistochemical staining methods to detecting GABAA receptorα1 subunit expression at hippocampus area(mainly: CA1, CA3 and dentate gyrus area). Manufacturing the hippocampal slices and whole-cell patch clamp skills detected the characters of CA1 pyramidal neuron of hippocampus,Results: The GABAAα1 expression of normal group are mainly concentrated in the hippocampus CA1 area, CA3 area and the dentate gyrus. the accumulated light density of GABAAα1 expression of the maternal separating 15min group has no significant difference in comparison with that of the normal group all three areas (p > 0.05), GABAAα1 accumulated light density of maternal separating 3 hour group was obviously decreased than of control group at the CA1 area (p < 0.01), but, the dentate gyrus and CA3 area was having no statistical significant (p > 0.05). The spontaneous firing rate of hippocampus CA1 pyramidal neurons of the maternal separating 3 hour group is 3.64±2.84 Hz, which was significantly fast than the normal group (1.15±0.69Hz, p<0.01), but there is no significant difference between the maternal separating 15min group(1.36±0.83) and the normal group(p>0.05).Conclusion: The stress of early maternal separating 3 hours through enhancing excitability of CA1 pyramidal neuron and the decreasing expression of GABAA receptorα1 at hippocampus, causing imbalanced of excitability and inhibitory function at the central nervous system, could enhance the epileptic susceptibility.
|
PDF Full Text Request