Objective To observe the effect of manual acupuncture stimulation of paired"Baihui"(GV 20)+"Shenmen"(HT 7)

GV 20+"Sanyinjiao"(SP 6)

and GV 20+non-acupoint on expression of melatonine(MT)and suprachiasmatic melatonin receptor 1(MT_1)and melatonin receptor 2(MT_2)mRNAs in insomnia rats

so as to explore their action difference and the underlying mechanism in improving insomnia.Methods Male SD rats were randomly divided into normal control(n=12)

model(n=8)

GV 20+HT 7(n=12)

GV 20+SP 6(n=11)

and GV 20+non-acupoint(n=10)groups.The insomnia model was established by intraperitoneal injection of Para-chlorophenylalanine suspension(50 mg/mL

50 mg/100 g)

once daily for 2 days.The abovementioned acupoints GV 20

bilateral HT 7

SP 6 and non-acupoints(the midpoint between the elbow-tip and armpit on the medial side of the upper-arm)were punctured with filiform needles and manipulated by rotating the needle for about 1 min which was repeated once again every 10 min during 30 minutes' needle-retaining.The treatment was conducted once daily for7 days.The expression levels of MT immunoactivity in the conarium tissue

and MT_1 and MT_2 mRNAs of the suprachiasmatic nucleus(SCN)region were detected using immunohistochemistry and fluorescence quantitative real time-PCR

respectively.Results After modeling

the expression levels of pineal MT(an increase of gray value means a decrease of immunoactivity)

SCN MT_1 and MT_2 mRNAs were notably down-regulated in the model group relevant to the normal control group(P<0.05

P<0.01).Following the treatment

the down-regulated expression levels of MT protein

and MT_1 and MT_2 mRNAs were obviously reversed in the GV 20+HT 7

GV 20 + SP 6 groups relevant to the model group(P<0.05

P<0.01).The therapeutic effect of GV 20+HT 7 was superior to that of GV 20+non-acupoint in up-regulating the expression of MT_1 mRNA(P<0.01)

and markedly superior to that of GV 20+SP 6 and GV 20+non-acupoint in increasing the sleep duration and in up-regulating the expression of MT_2 mRNA(P<0.01).No significant differences were found among the 3 treatment groups in up-regulating the expression of MT(P>0.05).Conclusion Manual acupuncture stimulation of GV 20+HT 7 and GV 20+SP 6 can improve the sleep disorder in insomnia rats

which may be related to its effects in increasing the levels of pineal MT protein

and MT_1 and MT_2 mRNAs in hypothalamic SCN.