Electroacupuncture at Fengchi(GB20) inhibits calcitonin gene-related peptide expression in the trigeminovascular system of a rat model of migraine

Most migraine patients suffer from cutaneous allodynia; however, the underlying mechanisms are unclear. Calcitonin gene-related peptide（CGRP） plays an important role in the pathophysiology of migraine, and it is therefore, a potential therapeutic target for treating the pain. In the present study, a rat model of conscious migraine, induced by repeated electrical stimulation of the superior sagittal sinus, was established and treated with electroacupuncture at Fengchi（GB20）（depth of 2–3 mm, frequency of 2/15 Hz, intensity of 0.5–1.0 m A, 15 minutes/day, for 7 consecutive days）. Electroacupuncture at GB20 significantly alleviated the decrease in hind paw and facial withdrawal thresholds and significantly lessened the increase in the levels of CGRP in the trigeminal ganglion, trigeminal nucleus caudalis and ventroposterior medial thalamic nucleus in rats with migraine. No CGRP-positive cells were detected in the trigeminal nucleus caudalis or ventroposterior medial thalamic nucleus by immunofluorescence. Our findings suggest that electroacupuncture treatment ameliorates migraine pain and associated cutaneous allodynia by modulating the trigeminovascular system ascending pathway, at least in part by inhibiting CGRP expression in the trigeminal ganglion.

Study on Preparation and Properties of Polyether Polytriazole Elastomers

To explore the application of click chemistry in the field of elastomer materials, propargyl-terminated ethylene oxide-tetrahydrofuran copolymer （PTP（E-co-T）） was prepared from hydroxyl-terminated ethylene oxide-tetrahydrofuran copolymer （P（E-co-T）） by end-etherisation modification. FTIR and ^13C-NMR results indicate that P（E-co-T）-terminated hydroxyl was etherified thoroughly, yielding the target product PTP（E-co-T）, and the content of terminated alkynyl of PTP（E-co-T） was evaluated to be 0.428 mmol.g^-l. Using a polyazide compound as a cross-linker, polytriazole elastomers with various functional molar ratio （R） values were prepared from PTP（E-co-T） by virtue of the CuAAC reaction. Mechanical property tests indicate that with the increase in R, the modulus E and stress Orb of the polytriazole elastomers first increase and subsequently decrease, whereas the strain first decreases and later increases. The mechanical properties of the polytriazole elastomers show a parabolic dependence on the R value. Near the stoichiometric ratio, E and Orb show maxima and the strain εb shows a minimum. Swelling tests demonstrate that the apparent molecular weight of polytriazole elastomer strands also first decreases and subsequently increases. At the stoichiometric ratio, the network structure possesses strands with a minimum apparent molecular weight and a maximum apparent density. Dynamic mechanical analysis reveals that the polytriazole elastomers presented damping peaks at approximately -64℃, corresponding to the glass transition of copolyether strands, and the elastomer exhibited the lowest dissipation factor tanδ at the stoichiometric ratio. Thermal analysis suggests that the weight-loss process of the polytriazole elastomer is characteristic of one-step decomposition, and the elastomer begins to decompose from polyether strands, not triazole groups.