Skip to main content


Fig. 3 | BMC Neuroscience

Fig. 3

From: Altered activity in the nucleus raphe magnus underlies cortical hyperexcitability and facilitates trigeminal nociception in a rat model of medication overuse headache

Fig. 3

Effect of inhibiting the NRM on CSD-evoked Fos-IR in the TNC. Chronic treatment with acetaminophen increased the number of neurons with c-Fos-immunoreactivity (Fos-IR) in the ipsilateral trigeminal nucleus caudalis (TNC) evoked by cortical spreading depression (CSD) (31.2 ± 9.9 and 20.0 ± 3.4 cells/slide for acetaminophen-treated and saline-treated vehicle-control rats, respectively, p = 0.010). In the control rats, CSD evoked expression of Fos in the TNC was enhanced by muscimol microinjection into the nucleus raphe magnus (NRM) (27.0 ± 7.2 cells/slide, p = 0.045 compared with saline microinjected controls). By contrast, microinjection of muscimol into the NRM did not alter the number of CSD-evoked Fos expressing neurons in the acetaminophen-treated rats 24.8 ± 3.4 cells/slide (p = 0.146 compared with saline microinjected acetaminophen-treated rats). a Photomicrographs show patterns of Fos-IR in the four experimental groups (scale bar 100 µm in each section and 50 µm in the inset). b Scatterplots comparing the number of CSD-evoked Fos-IR cells per slide after microinjection of muscimol or saline vehicle control into the NRM of the control rats and the rats treated chronically with acetaminophen

Back to article page