ABSTRACT
Expression of c-Fos, an immediate early gene, has accepted to be a marker of functional activity in neurons. This study was aimed to investigate the dental pain pathway and the affection of dental pain on other brain regions such as the cardiovascular regulation center using c-Fos immunohistochemistry. Expression of c-Fos in Sprague Dawley rats weighting 300 ~350 gm was examined 1.5 hr after dental pain elicited by intrapulpal injecton of 2 M KCl into upper and lower incisor pulps exposed by bone cutter. c-Fos positive neurons were demonstrated in the trigeminal nucleus caudalis and the ventroposterior medial nucleus of thalamus known to be a sharp pathway. Dental pain enhanced mean arterial pressure and heart rate. In addition, c-Fos expression was induced in the rostral ventrolateral nucleus of medulla oblongata, nucleus tractus solitarius, paraventricular nucleus and supraoptic nucleus of hypothalamus, central presser areas of systemic blood pressure. These results suggest that trigeminal nucleus caudalis and ventroposterior medial nucleus of thalamus plays vital roles in the transmission of dental pain besides, dental pain affected the central cardiovescular regulation centers, resulting to the elevation of systemic blood pressure.