c-Fos induction in the brainstem following electrical stimulation of the trigeminal ganglion of chronically mandibular nerve-transected rats

Abstract

Neuronal excitability in the trigeminal sensory nuclei (TSN) changes after nerve transection. We examined the effects of chronic transection of the trigeminal nerve on the c-Fos-immunoreactivity in the TSN induced 2 h after 10 min of electrical stimulation of the trigeminal ganglion (TG) at C-fiber activating condition (1.0 mA, 5 ms, 5 Hz) in urethane-anesthetized rats. In the non-transected control rats, stimulation of the TG induced c-Fos-immunoreactive cells (c-Fos-IR cells) mostly in superficial layers (VcI/II) of the nucleus caudalis (Vc) in its full extent along the dorsomedial-ventrolateral axis, but modestly in the rostral TSN above the obex, the principal, oral, and interpolar nuclei. Three days, 1, 2, or 3 weeks after transection of the inferior alveolar (IAN), infraorbital, or masseteric nerves, the stimulation of the TG induced c-Fos-IR cells in the central terminal fields of the transected nerve in the rostral TSN and magnocellular zone of the Vc. However, the number of c-Fos-IR cells in the VcI/II decreased inside the central terminal fields of the transected nerve and increased outside the fields. These results indicate that transection of the trigeminal nerve increases the excitability of TSN neurons that receive inputs from injured mechanoreceptors and uninjured nociceptors, but decreases it from injured nociceptors. The altered c-Fos responses may imply mechanisms of neuropathic pain seen after nerve injury.

Activation of dura-sensitive trigeminal neurons and increased c-Fos protein induced by morphine withdrawal in the rostral ventromedial medulla

“…Seven days after implantation of placebo or morphine pellets, animals were anesthetized with urethane (1.8 g/kg, i.p.) (41) and injected with either PBS or naloxone methiodide (1.0 µg/µl) through a 31-gauge injection cannula inserted into the guide. Injections were carried out over three minutes via a syringe pump and the cannula was removed five minutes following completion of the injection.…”

Sex‐ and age‐related differences in c‐fos expression in dog olfactory bulbs

“…Therefore, c-fos has strong connection with the cellular metabolism, apoptosis and cellular function. In particular, it can reflect the long-time memory ability of cells (Morgan et al 1987;Curran and Franza 1988;Morgan and Curran 1991;Hunt et al 2010;Abe et al 2013Abe et al L€ uscher et al 2016.…”