Effect of Electroacupuncture on Expression of 5-HT7 Receptor in Periaqueductal Gray and Plasma Calcitonin Gene-related Peptide in Migraine Rats

Abstract

To explore the analgesic effect of electroacupuncture(EA)by modulating 5-hydroxytryptamine 7 (5-HT7) receptor in periaqueductal gray (PAG) and plasma calcitonin gene-related peptide (CGRP). Forty-two male Sprague Dawley (SD) rats were randomly divided into control，model and EA groups, 14 rat in each one. The neurogenic migraine model was established by repeated electrical stimulation on sagittal sinus duramater. Intracranial electrodes were used in the control group without stimuli. The rats in the EA group received EA (0.5－1 mA, 2 Hz/15 Hz) at "Fengchi" (GB 20) for 10 min after dural electrical stimulation, once a day for 6 days. The expression of 5-HT7 receptor in the PAG was assessed by immunofluorescence and Western blot, respectively; plasma CGRP was measured by radioimmunoassay. Compared with the control group, the positive neuron number and protein expression of 5-HT7 receptor in PAG and plasma CGRP increased after model establishment (all P<0.001). The above mentioned indexes were reversed in the EA group compared with those in the model group (the positive neuron number and protein expression of 5-HT7 receptor, P<0.01; plasma CGRP, P<0.05). EA at GB 20 can down-regulate the expression of 5-HT7 receptor in the PAG and reduce the content of plasma CGRP in the rats of migraine.