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Objective: behavioral and electrophysiological evaluation methods, the effects of different neonatal maternal separation (NMS) time on the visceral pain sensitivity in young rats, and explore the use of NMS establish juvenile animal model of visceral hypersensitivity NMS appropriate time needed for further Recognizing NMS term harm to guide prevention and treatment of important guiding significance. Methods: 50 SD rats were randomly divided into NMS39, NMS60, NMS78, NMS120 group and control group (C group), each 10; NMS39 group 2 ~ 14d after birth and maternal separation daily 3h (8:00 - 11:00 am), continuous 13d, NMS60 group 2 ~ 21d after the birth of the first day and maternal separation 3h (8:00-11:00 am), continuous 20d, NMS78 group born after 2 ~ 14d (daily morning and afternoon respectively, and Maternal separation 3h (8:00-11:00 am; 14:00-17:00 pm), continuous 13d, NMS120 group 2 ~ 21d after birth, every morning, afternoon and female rats were separated 3h (8:00-11:00 am ; 14:00-17:00 pm), continuous 20d, no treatment control group, and maternal same cage. conventional breeding to 6 weeks of age, through different pressures colorectal distension (CRD) after stimulation of the abdominal withdrawal reflex score ( AWR), pain threshold measurements and external oblique discharge amplitude measurements pups intestinal pain sensitivity evaluation, determination of pups defecation fecal discharge points and glass beads time to evaluate colonic motility rats, rats were sacrificed, specimens descending colon for pathological examination. using SPSS11.0 software for statistical analysis, α = 0.05 for the significance test standards. Results: With the CRD pressure increases, the five groups pups AWR score and external oblique discharge values ??were gradually increased volatility ; when the CRD is 20mmHg, 40mmHg, 60mmHg when, NMS39 group, NMS60 group, NMS78 group, NMS120 group rats was significantly higher than in group C AWR scores, CRD is 80mmHg, the five pups AWR score between groups was not significant; when CRD to 15mmHg, 30mmHg, 45 mmHg, 60mmHg when, NMS39 group, NMS60 group, NMS78 group, NMS120 group pups external oblique discharge amplitude was significantly higher than that in group C; CRD is 75mmHg, the five groups pups abdominal oblique muscle discharge amplitude difference was not statistically significant; NMS39 group, NMS60 group, NMS78 group, NMS120 group and the pain threshold of rats in group C were 15.83 ± 5.05mmHg, 16.50 ± 8.40mmHg, 13.50 ± 2.88 mmHg, 16.00 ± 5.28 mmHg, 33.83 ± 4.31mmHg; NMS39 group, NMS60 group, NMS78 group, NMS120 AWR scores between groups pups, external oblique discharge and pain threshold amplitude differences were not statistically significant; 5 groups pups glass beads and discharge time no significant difference in fecal points; descending colon in each group showed no significant pathological tissue damage. Conclusions: Prolonged different neonatal rat maternal separation can cause pain threshold decreased, there visceral hypersensitivity; and this highly sensitive performance continued into childhood, but rats did not alter intestinal motility, and no change in bowel habit and stool changes, while no significant histopathological changes. adopt newborn rats after birth 2 ~ 14d given daily maternal separation 3h pups can create an ideal model of visceral pain hypersensitivity. Objective: neonatal maternal separation (NMS) to establish pups visceral hypersensitivity model of visceral hypersensitivity model rats was observed in the hypothalamic paraventricular nucleus (PVN ) and former cingulate cortex (ACC) of Fos protein expression, and to explore its participation in the formation of immature visceral pain hypersensitivity mechanism for the clinical prevention and harm caused by NMS to provide a theoretical basis for the disease. Methods: 32 SD newborn rats were divided into four groups factorial design, each 8. A1B1 group NMS group at 6 weeks of age to accept CRD, A1B2 group NMS group, 6-week-old did not give CRD, A2B1 group did not give NMS and 6 weeks to accept CRD, A2B2 group not given NMS, 6-week-old did not give CRD. A1B1, A2B1 group rats 2h after receiving stimulation and CRD A1B2, A2B2 group rats specimens PVN and ACC, immunohistochemical staining and computer image analysis system within the PVN and ACC Fos protein immunoreactive (FLI) cells semiquantitative analysis SPSS11.0 software package for statistical analysis, α = 0.05 for the significance test standards. Results: A1B1 group, A1B2 group, A2B1 group and A2B2 group of rats the PVN FLI cells were 50.61 ± 11.68,31.25 ± 7.28,43.67 ± 16.03 and 18.13 ± 3.41, ACC within the FLI cells were 53.48 ± 15.45,38.42 ± 11.67,35.02 ± 9.80 and 20.13 ± 2.08 . NMS and CRD rats 6 weeks of age can make the pups within the PVN and ACC FLI cells was significantly increased, the difference was statistically significant; NMS and ACC PVN rats induced FLI cells increased within the main effects were 10.03, 18.38, pups 6 weeks old pups PVN and ACC CRD caused FLI cells increased within the main effects were 22.45, 14.98; NMS and ACC and CRD on PVN FLI cells within no interaction effect Conclusion: Continuing NMS can cause neonatal pups central nervous system abnormalities and sensitized to accept noxious CRD stimulation can significantly cause PVN and ACC neurons Fos protein highly expressed in visceral pain hypersensitivity occur; PVN and ACC is the brain center pups visceral nociceptive signaling processes and perception of important areas, their activation and sensitization in NMS-induced visceral pain hypersensitivity pups play a crucial role.
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