Objective To explore possible functional mechanism of Toutongning Capsule（ 头痛宁胶囊） on tension headache（ TH）. Methods Injected triphosadenine into neck muscles to induce TH. Eighty SD rats were randomly divided into model group

control group and the Tongtongning high

middle and low dose group

with 16 rats each. The Tongtongning high

middle and low dose group were respectively given Tongtongning capsule suspen-sion 760

380

190 mg / kg for continuous gavage of seven days. The model and control group was continuously perfused with normal saline of equal dose for seven days. Observed the jaw-opening reflex amplitude and latency before and after treatment. And examined nitric oxide synthase（ NOS）

5-hydroxytryptamine（ 5-HT） and glutamic acid（ Glu） level in brain tissue and serum. Results Jaw-opening reflex latency in all dose groups of the Toutongning capsule remarkably lengthened after treatment（ P < 0. 05）

and Jaw-opening reflex latency improved more obviously with Toutongning dose increasing（ P < 0. 05）. Jaw-opening reflex thresholds in all Toutongning dose groups all remarkably increased compared with the model group（ P < 0. 05）. There was no statistical difference in different dose groups（ P > 0. 05）. Activity of NOS and the levels of 5-HT in plasma in all Toutongning dose groups remarkably increased while the levels of Glu remarkably increased compared with those of the model group（ P < 0. 05）. The improvement showed increase with dose increase（ P < 0. 05）. Conclusion Toutongning capsule could influence the attacks of TH by affecting thresholds of jaw-opening reflex in head muscles and skin and by changing pain sensitivity of muscular fasciae in head. The mechanism may be related to decreasing activity of NOS

decreasing 5-HT and increasing level of Glu.