Effect Of Electroacupuncture On Learning And Memory Ability And The Expression Of NR2B Receptor In Different Brain Regions During Morphine Withdrawal In Rat

Objective:To observe rats’ learning and memory ability, synapatic structure parameters, the expression of NR2B receptor in different brain regions by electroacupuncture during morphine withdrawal.Methods:48 male SD rats were randomly divided into control group(group A), model group(group B), acupuncture group(group C) and electroacupuncture group(group D),12 in each group. Except the group A, the rest three groups were injected with escalating doses of morphine hydrochloride subcutaneous on back and naloxone waere administrated 3 h after the last injection perceptive rapid withdrawal. Morphine withdrawal model was established successfully through rating the scores of withdrawal symptoms. The groups of experiment rats were observed by different methods:(1) observe the weight changes at different time points;(2) apply Morris water maze navigation and probe trail test, record platform escape latency and times of cross platform;(3) HE staining, electron projection electron microscope to observe each group’s PFC, NAc, AMG, VTA brain tissue pathological morphology;(4) measure different brain regions’ synaptic interface active region length, postsynaptic density, the width of synaptic cleft and synaptic interface curvature changes and the impact of different methods for it;(5)western blot method to detect NR2B protein expression changes of different brain areas and the impact of different methods for it;(6) PT-PCR method to detect NR2BmRNA expression of different brain areas and the impact of different method of it.Results:(1) In addicted rats after morphine withdrawal, the weight were significantly decreased in group B, and the weight gain was slow, the difference was statistically significant (P<0.01), acupuncture and electroacupuncture can spur the recovery of body weight growth trends in rats after withdrawal, the difference was statistically significant compared with group B (P<0.05, P<0.01).(2) The Morris water maze navigation test, according to the results of group B, platform escape latency of rats significantly reduced in group D(P<0.01), decreased in group C(P<0.05); In Morris water maze probe trail, group C compared with group B, the crossing platform number increase (P<0.05), the group D was significantly increased (P<0.01).(3) HE dyeing observation showed that compared with group B, group C and D’s PFC, NAc, AMG, VTA brain neural tissue edema, cell loss, nerve cells atrophy, surrounding cells and broadening gap has obviously improved, the group D’s effect was better than that of group C. Electricity transmission electron microscope showed that compared with group B, group D in PFC, NAc, AMG, VTA brain neurons form in the area, endoplasmic reticulum degranulation, fracture organelles such as mitochondria cristae damage have improved significantly. (4) Synaptic structural parameters, according to the comparison of group B, the group D’s synaptic active area in length and the thickness of postsynaptic density material in PFC, NAc, AMG, VTA have increased significantly (P<0.05), in terms of PFC synaptic gap width decreased obviously (P<0.05), in brain areas AMG significantly reduced (P<0.01); group C in terms of width of synaptic cleft in AMG regions decreased significantly (P<0.01), the width of synaptic cleft and curvature of synaptic interface in other brain regions, compared with group B, have no statistical difference (P>0.05).(5) According to the results of Western blot-NR2B protein expression in the area of PFC group B decreased significantly (P<0.01), compared with the group B, group C and D were significantly increased (P<0.01), and group D obviously than group C(P<0.01); NR2B protein in NAc brain region of group B was significantly lowered (PO.01), compared with the group B, group C and D were significantly increased (P<0.01), and group D obviously than group C(P,0.01); In AMG brain region, NR2B protein expression of group B was decreased significantly (P<0.01), compared with the group B, group C and D were significantly increased (P<0.01), and group D obviously than group C(P<0.01); NR2B protein expression in the VTA brain region, group B was decreased (P<0.01); compared with the group B, group C and D were significantly increased (P<0.01), and group D obviously than group C(P<0.01).(6) According to the results of RT-PCR, NR2BmRNA expression in the area of PFC of group B was decreased (P<0.05), compared with group B, the expression was increased in group C(P<0.05), though an upward trend in group D, there was no obvious difference (P>0.05); NR2BmRNA expression in the area of NAc of group B was decreased (P<0.05), compared with group B, the expression was increased in group C(P<0.05), though an upward trend in group D, there was no obvious difference (P>0.05); In the area of AMG group B’s NR2BmRNA expression was decreased (P<0.05), compared with group B, the expression was increased in group C(P<0.05), though an upward trend in group D, there was no obvious difference (P>0.05); In the area of VTA group B’s NR2BmRNA expression was decreased (P<0.05), compared with group B, the expression was increased in group C(P<0.05), though an upward trend in group D, there was no obvious difference (P>0.05).Conclusion:(1) Both acupuncture and electroacupuncture could improve the weight lose of morphine withdrawal rat. Electroacupuncture could shorten the escape latency of rats after morphine withdrawal, increase the times of across the platform, restore the damaged the ability of learning and memory, and the effect is better than acupuncture.(2) The electroacupuncture can alleviate nerve cell edema, improve neurons and synapses synaptic ultrastructure damage in different brain regions after morphine withdrawal, increase the thickness of synaptic active area length and postsynaptic material interface, and specificity of shortening the prefrontal cortex and the amygdala synapses cleft distance, enhance the strength of synaptic connections, improve the synaptic function, its effect is better than acupuncture.(3) The electroacupuncture could restore the glutamate receptor NR2B subunits expression in the protein and the gene level of different brain regions after morphine withdrawal, and the effect was positively correlated with better ability of learning and memory in morphine withdrawal rats.