Effect of Restraint Stress on the Behaviors and Neuronal Activities in the Prenatal Opioid Exposed Rats.

• Main Authors: Wu, Ming-Long, 吳明龍
• Other Authors: Kuo, Chung-Chih
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/23928405344564669105

碩士 === 慈濟大學 === 生理暨解剖醫學碩士班 === 104 === 　　The infants born by the pregnant women with opioid addiction or opioid replacement treatment would be affected by the opioid agonists from the placenta during their development. The opioid agonists have the potential to disrupt development of central nervous system. The introduction changes the release of neurotransmitters and the brain structure. The children born by opioid abuser present long-term neuropsychological problem during school years, including the dysfunction in intellectual ability and emotional control. In this study, the anxious and depression behaviors and neuronal activities of amygdala and hippocampus during open field test and elevated plus maze task were compared in the rats exposed to 3 opioid agonists prenatally including morphine, methadone and buprenorphine and to saline as control group. In open field test, the results show that there is no significant difference of locomotor behaviors in open field test between the 4 groups or the effect of restraint stress. Many amygdala units changed the neuronal activities when the rat explored in the open field for 30 minutes. The neuronal response of amygdala units with decreasing firing was reduced only in control group under stress but not in the 3 prenatal opioid exposed groups. For the hippocampal neurons, some units in 4 groups showed the decreasing firing activities during exploring the open field. Under the restraint stress, the neuronal activities of hippocampal units with decreasing firing was not declined much in the control groups but still declined in the prenatal opioid exposed groups. In the elevated plus maze task, the results showed that there is no significant difference of entry and time in the opened arm between the 4 groups without restraint stress. Under the restraint stress, the entry and time in the opened arm were reduced in all 4 groups but the decrease was not significant only in the prenatal buprenorphine exposed group. Some neuron changed their firing rates when entering the open arm. Restraint stress reduced the change of hippocampal units with increasing firing in the saline, morphine and methadone groups but not in the buprenorphine group. The firing rates of hippocampal units with decreasing firing were also reduced under restraint stress in the prenatal opioid exposed group but not in the control group. For the amygdala units with increasing firing, the increases of amygdala units with increasing firing were reduced under the restraint stress. The firing rates of amygdala units with decreasing firing were also reduced under restraint stress in the prenatal opioid exposed group but not in the control group. Summarized the results from open field test and elevated plus maze, the rat exposed to buprenorphine prenatally performed more anxious and depression behaviors under the stress, especially in the elevated plus maze task. The neuronal responses in amygdala and hippocampus under stress were also affected in the rats exposed to opioid prenatally. It was suggested that the sensitivity to stress for performing the anxious behaviors is associated with the neuronal responses affected by the prenatal exposure of opioid.