La Stimolazione elettrica trigeminale modifica l'espressione genica di c-Fos e diminuisce le crisi epilettiche nel ratto

Aim: this study evaluated in rats, which brain structures could mediate the Trigeminal nerve stimulation (TNS) antiepileptic action. Immunohistochemical labeling was used to assess TNS effects on the regional brain expression ofc-fos. Anesthetized rats were implanted in the infraorbital branch of the trigeminal nerve with an electrode connected to an electrical stimulator. After recovery, rats were given 3h of TNS (continuous cycle: 30sec ON, 5min OFF; 30Hz, 500μs, 3.5mA). A control group underwent same surgery but did not undergo TNS. Induction of crisis were made throught PTZ injection (70mg/Kg/4ml). The number ofFospositive cells in TNS animals, compared to controls, showed an increase of about 4 times in the amigdala (P<0.0001), of 2.8 times in the somatosensory area of the frontoparetial cortex (P<0.01) and of 10.7 times in the endopiriform nucleus (P<0.0001). In all these structures, a significantly larger (p<0.0001) number of labeled cells (x7.7, x6.6 and x36.6 times, respectively) was detected contralaterally to the stimulation side. Furthermore, a decrease of crisis activity period in TNS than in Sham (P= 0,0172) and the different category behavioral within the sperimental group showed that in TNS were express mostly mild crisis type than Sham. These data support a marked TNS action on brain structures which may play a pivotal role in seizure initiation and regulation.