Establishment of chronic inflammatory migraine models and expression of P/Q type calcium channel Cav2.1

Objective To explore the establishment of models of chronic inflammatory migraine and preliminary study on the relationship between P/Q type calcium channel Cav2.1 and migraine. Methods Eighteen C57BL/6 mice were randomly divided into control group, model group and sham-operated group (n=6). In model group, the dura mater of mice were consciously stimulated by inflammatory soup, and in the control group, interstitial fluid was given. Eight times after the treatment, behavioral observation of irritable condition of mice (scratching frequency changes) was performed; immumohistochemical staining was employed to detect the c-fos expression in the trigeminal nucleus caudalis and calcitonin gene related peptide (CGRP) expression in the eriaqueductal gray aqueduct. Fluorogenic quantitative PCR and Western blotting were used to detect the P/Qtype calcium channel Cav2.1 mRNA and protein expressions. Results Behavioral results showed that the scratching frequency of the model group within 2 h of final administration ([497±78] times) was significantly higher than that of the control group ([117±34] times, P<0.05). Number of neurons with c-fos gene positive expression in the model group (220±20) was significantly larger than that in the control group (30± 4, P<0.05). The mean density of CGRP expression (13.00±0.01) was significantly higher than that in the control group (4.50±0.02, P<0.05). The relative mRNA expressions of Cav2.1 gene in the trigeminal nerve and trigeminocervical complex of model group increased (1.60±0.17) and (1.42±0.15) times as compared with those in the control group (P<0.05); the gray values of Cav2.1 protein in the cortex and trigeminocervical complex of model group were increased (1.50 ± 0.02) and (1.30 ± 0.01) times as compared with those in the control group (P<0.05). Conclusion Repeated inflammatory stimulation of the dura mater can provide experimental basis for chronic migraine models, and P/Q type calcium channel Cav2.1 may regulate the occurrence of migraine via up-regulated expression. Key words: Migraine; P/Q type calcium channel Cav2.1; C-fos; Calcitonin gene related peptide