Abstract
Purpose: The purpose of this study was to clarify whether an experimental occlusal interference was recognized in the brain as stress.
Methods: 11-week-old male Wistar rats were used. They were divided into four groups: the control group, the immobilization stress group, the water immobilization stress group and the occlusal interference group, and each group consisted of six rats. Blood was sampled after the stress stimulation, and the concentration of corticosterone in blood was analyzed. In situ hybridization was then performed, and the expression of c-fos mRNA in the brain was observed. The eight regions of observation were amygdaloid, piriform cortex, hippocampus, cigulate cortex, paraventricular nucleus of the hypothalamus, locus coeruleus, raphe magnus nucleus, and central gray.
Results: c-fos mRNA positive cells were found in the eight regions of the brain, though the experimental occlusal interference group was different in the degree of c-fos mRNA expression in comparison with the two immobilization stress groups. Also, differences in right and left brain hemisphere of the c-fos mRNA positive cells were found in amygdaloid and piriform cortex of the occlusal interference group. The concentration of corticosterone in blood was high in the water immobilization stress group, the immobilization stress group, the occlusal interference group and the control group in this order.
Conclusions: The response caused by the experimental occlusal interference was clearly manifested as stress.
