S-Space College of Dentistry/School of Dentistry (치과대학/치의학대학원) Dept. of Dentistry (치의학과) Journal Papers (저널논문_치의학과)
Efffects of pain inducing agents on voltage dependent calcium currents in the trigeminal ganglion
- Park, Kyungpyo; Kim, Seong-Ah; Kim, Youn-Bae; Kim, Joong-Soo; Lee, Jong-Heun
- Issue Date
- The Korean Academy of Oral Biology
- International Journal of Oral Biology 26:1-6, 2001.
- trigeminal ganglion(TG); voltage dependent Ca^2+ current(I_Ca); bradykinin; histamine; eugenol
- Trigeminal ganglion (TG) neurons are primary sensory neurons involved in the transmission of orofacial sensation, including pain. It is known that intracellular free calcium concentration plays a critical role in neurotransmitter release. In the present study, we examined the effects of pain-inducing agents, bradykinin and histamine, on voltage dependent Ca^2＋ current (I_Ca) and compared these with the effects of the analgesic agent, eugenol. I_Ca was measured using a whole-cell patch clamp method. Bradykinin (10μM) inhibited I_Ca in TG neurons. Maximum inward I_Ca was reduced by 26% by bradykinin compared with the controls (n＝13, p＜0.05). Decreased I_Ca induced by bradykinin did not recover to the prestimulus level after washing out bradykinin. In contrast, histamine (100μM) increased I_Ca by 25% compared with controls (n＝7,p＜0.05) in an irreversible manner. Eugenol (250μM), commonly used to produce analgesia in dental clinics, decreased I_Ca to 22.6% (n＝9,p＜0.05) and this effect on the I_Ca was reversible. although the effect of eugenol on the I_Ca was consistent, the effects of the two pain-inducing agents, bradykinin and histamine, were different. Our results suggest that the modulation of I_Ca in TG neurons is not a decisive factor underlying the pain mechanism evoked by pain-inducing agents.