Effects of repeated tooth pulp stimulation on concentrations of plasma catecholamines, corticosterone, and glucose in rats

Abstract

In this study, we examined whether tooth pulp stimulation (TPS) affects the stress responses in anesthetized rats. As for stress response indices, we monitored changes in the concentrations of plasma catecholamines (CAs) (adrenaline, noradrenaline, and dopamine), corticosterone (CS), and glucose (Glu). We observed that repeated TPS attenuated plasma adrenaline, dopamine, CS, and Glu levels compared with those of sham-TPS. After administering naloxone, an opioid antagonist, repeated TPS reversed the decreases in plasma CAs, CS, and Glu. These findings showed that the effects of repeated TPS may be mediated by endogenous opioid administration. Our findings suggest that repeated TPS can induce stress-analgesia and that an endogenous descending pain modulation system exists.

Keywords:

• Catecholamines
• Corticosterone
• Descending pain modulation
• Glucose
• Tooth pulp stimulation

Acknowledgements

This work was partly supported by a Hyogo College of Medicine Research Grant for M. Hasegawa and a Grant-in-Aid for Scientific Research (C) JSPS KAKENHI (21592438, 25462978).