Effect of Paeonia lactiflora, a traditional Chinese herb, on migraines based on clinical application and animal behavior analyses.

Paeonia lactiflora (PL) was widely used for pain relief, but its effects on migraine headaches remain unclear.The aim of the present study was to investigate the effects of PL on migraine headaches.First, we found that PL was frequently used in Taiwan for headache treatment based on data from Taiwan's National Health Insurance Research Database. Migraine was induced through the intraperitoneal injection (i.p.) of nitroglycerin (NTG, 10 mg/kg) in rats. Pretreatment with PL was administered orally 30 min prior to the NTG i.p. Migraine headache behavior was observed by video-recordings. Finally, the rats were sacrificed and brain was removed for immunohistochemistry staining analysis.The frequency and total time spent rearing up and sniffing in exploratory behavior, and walking in locomotor behavior, were reduced in the NTG group compared with the control group (all p < 0.001). This reduction could be ameliorated by pretreatment with PL 1.0 g/kg (all p < 0.05). Total time spent in the light chamber was lower in the NTG group compared with the control group (p < 0.05); this could be ameliorated by pretreatment with 1.0 g/kg PL (p < 0.05). The rats in the NTG group spent longer time on the smooth surface than those in the control group (p < 0.001); this could be shortened by pretreatment with 0.5 and 1.0 g/kg PL (both p < 0.01). The traveling distance of rats in the NTG group was shorter than in the control group (p < 0.001); rats given 1.0 g/kg PL had a longer traveling distance than those in the NTG group (p < 0.01). Both c-fos and CGRP immunoreactive cells increased in the TNC in the NTG group compared with that of the control group (both p < 0.001); this increased could be reduced by pretreatment with PL 0.5 and 1.0 g/kg (both p < 0.05).Pretreatment with PL ameliorated migraine headache behaviors in the NTG-induced migraine rat model, suggesting pretreatment with PL is beneficial for migraine headache treatment. This effect of PL is related to the decrease of c-fos and CGRP in the TNC. However, still there are too many methodological limitations which need to be overcome in further experiments to support the data.