Kisspeptin, the peptide product of KiSS-1 gene, is potent secretagogue of gonadotropin-releasing hormone and has important role in puberty onset. Previous studies have shown that kisspeptin receptor, GPR54, is expressed in the dorsal root ganglia and dorsal horns of the spinal cord in addition to hypothalamus, amigdala and some different peripheral tissues. There is quide only limited data on possible involvement of kisspeptin system in peripheral nociceptive transmission. The aim of this study was to investigate the effects of kisspeptin on intracellular calcium ([Ca2+]i) levels in isolated rat trigeminal ganglion (TG) neurons. TG neurons were isolated from neonatal rats, plated on poly-D-lysine-coated coverslips and maintained in neurobasal medium supplemented with B27. These neurons were loaded with 1μM Fura-2 AM and Ca2+ responses were assessed by using the fluorescent ratiometry. Fura-2 loaded cells were excited at 340 and 380nm, and emission was recorded at 510nm by using calcium imaging system. Changes in free [Ca2+]i were determined by the 340/380nm ratio in each neurons. All data were analyzed by using unpaired t test, with a 2-tailed P level of <.05 defining statistical significance. The increases in [Ca2+]i as % of preceding control (baseline) levels was 141.9±5.7 % (p < 0.001, n=28) produced by 1μM kisspeptin treatment. We performed same experimental procedure in extracellular Ca2+ free conditions. Similarly, kisspeptin significantly elevated [Ca2+]i in TG neurons (100.0±0.0 % and 116.9±4.8 % in baseline and 1µM kisspeptin, respectively, n= 25 cells, p<0.01). Results from this study for the first time indicates that kisspeptin increases [Ca2+]i in isolated TG neurons in normal Ca2+ concentrations and Ca2+ free conditions. We can suggest from these data that kisspeptin may have a role for nociceptive transmission. Further investigations are needed to clarify the mechanism(s) of kisspeptin action on calcium signaling in TG neurons.