Fig. 2

Heat evoked activity of units with afferent input from the exposed cranial dura mater recorded in the spinal trigeminal nucleus caudalis. a Heat sensitivity was obtained at baseline and after all infusions as visualized and at the time points shown in Fig. 1. The temperature at the dura was first ramped from 32 to 44 °C and held for 30 s. In a second protocol, the temperature was rapidly stepped from 32 to 36, 40 and 44 °C. b The response of eight spinal trigeminal neurons at baseline and after incremental additions of NOX-C89 0.05–5 mg/kg (mean ± sem) during the temperature protocols shown in panel A. c Average activity during the whole period of elevated temperature was increased above baseline. Similarly, all temperature steps increased neuronal activity. NOX-C89 infusion at all doses inhibited the neuronal response to thermal stimulation (*p < 0.05). Data are mean ± SEM