Abstract: OBJECTIVE:To investigate the role of adenosine triphosphate(ATP) purinergic signaling in mast cells(MCs) modulated by heat to further understand the molecular mechanisms of moxibustion.METHODS:Skin temperatures induced by monkshood cake moxibustion were evaluated by measuring the Neiguan acupoint(PC 6) from 31 participants with a digital thermocouple thermometer.Temperatures of 43 ℃ and 52 ℃ were applied to cultured human leukemia mast cell line HMC-1 in vitro.Calcium fluorescence was applied to detect intracellular Ca~(2+)([Ca~(2+)]_i).Extracellular ATP contents were measured by luciferin-luciferase assay.RESULTS:Maximum skin temperatures mostly ranged from 40-45 ℃,but some reached up to50 ℃.Both 43 ℃,and 52 ℃ induced MC degranulation,which was accompanied by an increase in[Ca~(2+)]_i and ATP release.Complexing extracellular Ca~(2+) with 5 mM ethylene glycol-bis(β-aminoethyl ether)-N,N,N',N'-tetraacetic acid(EGTA) inhibited the noxious heat-induced elevation of[Ca~(2+)]_i and prevented the enhanced ATP secretion by those cells at 52℃ but not 43 ℃.CONCLUSION:Monkshood cake moxibustion can generate heat sufficient to trigger cellular events of MCs,including degranulation,[Ca~(2+)]_i elevation,and ATP release,suggesting that purinergic signals originating from MCs are possibly the initiating response of acupoints to moxibustion.

Key words: Fire toxin syndrome, Mast cells, Cell degranulation, Calcium, Adenosine triphosphate, Moxibustion