S-Space College of Dentistry/School of Dentistry (치과대학/치의학대학원) Dept. of Dentistry (치의학과) Journal Papers (저널논문_치의학과)
Effects of various neurotransmitters on the intracellular calcium concentration in trigeminal ganglion neurons
- Park, Kyungpyo; Kim, Joong-Soo; Lee, Jong-Heun
- Issue Date
- The Korean Academy of Oral Biology
- International Journal of Oral Biology.22: 223-228, 1997.
- Functional neurotransmitter receptors which elevate intracellular free calcium concentration ([Ca2i]j have been identified in freshly isolated trigeminal ganglion (TG) neurons in neonatal rat pups. Measurement of [Ca2´], was performed using fura-2 acetoxymethyl ester (Flea-2) based ratio microspectrofluorimetry. In our experiments only small sized neurons (<30 m) according to somatic diameter were used. In single intact neurons, the expression percentage and magnitudes of [Ca´+], increase responding to each agonist were determined. Application of bradykinin (BK), substance P (SP), calcitonin gene related peptide (CGRP), ATP and capsaicin elevated [Ca"], in the expression percentages of 24%, 37%, 31%, 77% and 50%, respectively, and elevated [Ca 2´], from 1.630.04 (MeanS.E) to 1.920.05, from 1.360.08 to 1.880.12, from 1.33 0.03 to 1.610.09, from 1.350.04 to 2.20.15 and from 1.260.06 to 2.90.26, respectively. The purinergic receptor which respond to ATP was most frequently expressed (77%). A [Ca`], increase in response to all neurotransmitters was transient in nature, except in response to capsaicin. Increase of [Ca2i], evoked by capsaicin was not transient: [Ca2´], was maintained at a higher concentration than the prestimulus level. The magnitude of [Ca 2´], increase evoked by capsaicin was bigger than for any other neurotansmitters. Our results show that a subpopulation of trigeminal ganglion neurons with small diameter express functional receptors responsible for elevating [Ca2i], coexisting with other neurotransmitter receptors in the early neonatal stage. Our data may have implications for studying orofaciai pain transmission which is associated with intracellular calcium increase.