Functional Expression of K_ATP Channel on Human Periodontal Ligament Cells

Objectives: Adenosine-5’-triphosphate (ATP) has been mentioned in dental research on multiple levels, such as inflammation, mechanical strain and pain, making the system particularly relevant for the specific challenges in the oral cavity. There are studies showing human periodontal ligament (PDL) cells respond to mechanical stress by increasing ATP release, which participates in bone resorption or bone homeostasis.
Methods: In this study, we used the RT-PCR and patch-clamp technique to investigate the presence of K_ATP channel subunits and influence of ATP on the K_ATP channel opening on PDL cells.
Results: We observed transcripts for Kir6.1, Kir6.2 and Sur2B mRNAs isolated from the human PDL cells. In inside-out patch mode, the single channel conductance was 163 pS at symmetrical K⁺ concentration of 140 mM and inward rectification was seen at the ATP-free bath solution. The reversal potential of the currents was found to be 0 mV at symmetrical concentration (140 mM) of K⁺ in bath solution. The single channel currents were almost blocked by adding 5 mM ATP in the bath solution. However, the currents were not blocked by 100 μM glibenclamide, a subunit specific K_ATP channel blocker.
Conclusions: These results indicate that human PDL cells express K_ATP channels which are not sensitive to glibenclamide. This research was supported by Basic Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2014R1A1A2054241) and (2015R1D1A3A01018700)