Abstract
The perception of stress by an individual activates the CNS with two major consequences: the neuroendocrine system responds via the HPA axis and the autonomic nervous system responds, causing sympathetic nerve termini to locally release catecholamines. Each of these processes have a potential cost to the body when allostasis is either called upon too often or is inefficiently managed,and that cost is referred to as "allostatic load". We investigated the effects of biting on restraints stress-induced high blood pressure and core temperature as an allostatic load accumulation, and chemical mediators in the serum for further define. Biting of a wooden stick during restraint resulted in a significant reduction of blood pressure at 30, 45, 60 and 75 min, and significant inhibition in core temperature at 30, 60, 120, and 180 min compare with restraint-only rats and these differences are visible in the comparison of infrared thermal images of the restraint-only and restraint with biting rats after 60 min. Biochemical analysis revealed that plasma interleukin(IL)-1β, IL-6, and leptin were significantly suppressed by biting and thyroid stimulating hormone was significantly increased by biting. These results suggest a possible anti-stress effect of biting and an important role of para-functional masticatory activity in coping with stressful events.
