Objective To investigate the change in expression of hippocampal neuronal 5-hyroxytryptamine1A(5-HT1A) receptor in a mouse model of chronic restraint stress.Methods Forty BALB/c male mice aged 6-9 months weighing 25-35 g were randomly divided into 2 groups ( n =20 each): normal control group (group C) and chronic restraint stress group( group S).In group S,the model of chronic restraint stress was established described by Wood et al.Tail suspension test,light-dark test and Morris water maze test were performed respectively at 1 d after successful establishment of the model.Immobility time,staying time in light compartment,and escape latency and frequency of crossing the original platform were recorded respectively in tail suspension test,light-dark test and Morris water maze test.Then the animals were sacrificed,hippocampi were removed for determination of the expression of 5-HT1A receptor in CA1 and CA3 regions of hippocampal neurons by immuno-histochemistry.ResultsCompared with group C,immobility time and escape latency were significantly prolonged,staying time in light compartment was shortened,frequency of crossing the original platform was decreased,and the expression of 5-HT1A receptor in hippocampal neurons was down-regulated in group S ( P ＜ 0.05 or 0.01 ).ConclusionChronic restraint stress can induce cognitive impairment in mice by down-regulating the expression of 5-HT1A receptor in hippocampal neurons.

Objective To investigate the change in the function of the motor nerve fibers of the sciatic nerve of rat following injection of different neurolytic drugs. Methods Thirty-five SD rats weighing 350-380 g were randomly divided into 7 groups ( n = 5 each): group C received normal saline; group Ad adriamycin 5 mg/ml;group Aa anhydrous alcohol; group Pg1 8% phenol-glycerol; group Pg2 10% phenol-glycerol; group Pg3 12% phenol-glycerol and group Ci cidomycin 4000 U/ml. 0.2 ml of the different neurolytic drugs was injected at the points where the branches of the sciatic nerve entering semi-membranous and adductor magnus muscles. The action potential and conduction velocity of motor and sensory nerve fibers were measured at 21 d after injection. Results The conduction velocity of sensory nerve fibers was 0 in each group. The conduction velocity and action potential of the motor nerve fibers were significantly decreased in group Ad, Aa, Pg1, Pg2, Pg3 and Ci as compared with group C (the control group). The action potential and the conduction velocity were significantly higher in group Ad than in other neurolytic drug groups. The potential and the conduction velocity were the lowest in group Aa and Pg3.The conduction velocity in group Pg1, Pg2, Ci was comparable. Conclusion 5% adriamycin seems to be a better neurolytic drug with less interference with function of motor never fibers.