Roles Of Hippocampal-Prefrontal Cortical Circuits In Morphine Addiction Memory And Effects Of Ethanol Extract Of Bidens Pilosa In Neural Behaviors

Drug addiction(psychological addiction)is a kind of strong drug related memory,which is called addiction memory.The hippocampus(HP)-prefrontal cortex(PFC)circuits are the key circuits of spatial memory.However,it is unknown about the role of HP-PFC circuits in addiction memory.Firstly,we investigated the roles of rat HP-PFC circuits in expression,extinction of morphine conditioned place reference(CPP),and in normal memories,depression or anxiety models.CPP addiction model was set up by using constant dose injection of morphine(10 mg/kg)for 8 d.Then unilateral ventral hippocampus(VH)and the infralimbic area(IL)or the prelimbic area,PL)were damaged by injection of Kaninic acid(KA).The lesion groups are including ipsilateral PL and VH(VH-PL),unilateral PL and contralateral VH(VH/PL,disconnection of the VH-PL circuit;lesion before expression test);Ipsilateral IL and VH(VH-IL),unilateral IL and contralateral VH(VH/IL,disconnection of the VH-IL circuit;lesion after expression test).Then the animals were test for expression,extinction,kindling of CPP,then for passive avoidance,forced swimming,Morris water maze experiment and histological examination were conducted.Results:(1)the histological data,,loss of neurons were observed in the VH,IL or VH areas(vs.control group(Sham))but areas outside are normal.(2)CPP expression: PL/VH damage causes a decline in the CPP score vs.Sham.(3)CPP extinction: Sham group did not extinct,and scores of the four lesion groups were decreased.(4)CPP kindling:The scores of the VH-PL,VH/PL and VH/IL groups were at random levels,and the scores of VH-IL group significantly increased.(5)Passive avoidance: except the VH/PLgroup,the latencies of the rest groups increased vs.Sham.(6)Forced swimming:No difference between the Sham and other groups.(7)No difference between the Sham and other groups.The key findings of this chapter is: expression of rat morphine CPP memory depends on the intact of the VH-PL circuit.The VH-PL circuit is from HP-PFC circuits,is one of the key circuits involved in memory expression of morphine addiction memory.We studied the effects of the ethanol extract of Bidens pilosa L.(EBP)on memory and emotional behavior of rats and the effect of EBP on ileum smooth muscle and aortic ring contraction function next.Wistar rats were fed by four doses of EBP(0mg/kg(control),25 mg/kg(low),50 mg/kg(middle),and 100 mg/kg(high)).Then the open-field,passive avoidance and Morris water maze tasks were performed.Results:(1)Open field: In EBP treated groups,the times of entry the central region is lower than control group.(2)Passive avoidance: Compared with control group,there was no significant difference.(3)Water maze: EBP treated animals can find the submerged platform faster in training phases and stay for more time in the target quadrant,passed the platform field for more times vs.control group.(4)EBP can make ileum smooth muscle contract,even the smooth muscle had been relaxed by high dose of epinephrine(E).And atropine can not reverse the effects of EBP.Therefore,the contraction effect of the EBP on ileum should not be got by acetylcholine(ACh)M receptor.(5)High dose EBP made the aortic ring to relax.ACh can not inhibit the contraction effect of E on the aortic ring,but EBP can make arterial ring to relax.Moreover,the relaxation effect of EBP can not be reversed by atropine.Therefore,the ACh M receptor should not be the target of effect of EBP in aortic smooth muscle relaxation.In present thesis,the significant findings are: 1.We firstly proved that the VH-PL circuit is one of the key circuits to expression of rat morphine CPP.2.The BP can improve memory,promote the intestinal smooth muscle contraction and relaxation of aortic smooth muscle.But the effects of EBP on smooth muscles would not be the cholinomimetic effect of BP.