TRPV1-Mediated Entry of QX-314 Leads to Inhibition of Nociceptive Input as Measured by BOLD fMRI in Mice using Thermal Stimulation

Simone Claudia Bosshard¹, Florian Stuker¹, Constantin von Deuster¹, Markus Rudin^1,2

To study nociceptive processing in mice, a thermal stimulation paradigm using an infrared laser source for forepaw stimulation was developed. The skin of the forepaws was heated to 45C or 46C for 60s, using a feedback system to control the temperature. The stimulation led to significant BOLD changes in the somatosensory cortex and the thalamus. For modulation, a combination of QX-314 and capsaicin was injected into the forepaws, inducing a selective nociceptor block, which led to an abolishment of the BOLD signal. Either solution applied alone did not lead to a decrease in BOLD signal changes.