Comparing The Pathway Of ATP Inhibition On VGCCs In Rat Trigeminal Ganglion Neurons Between Chronic Constriction Injury To The Infraorbital Nerve Rats And Normal Rats

Objective The trigeminal neuralgia (TGN) model was established by infraorbital nerve constriction through lower edge of cheekbone. The ethology examination and the whole cell patch-clamp technique were used to compare the pathway of ATP inhibition on voltage-gated calcium channels (VGCCs) in trigeminal ganglion (TG) neurons between chronic constriction injury to the infraorbital nerve rats and normal ratsMethods The TGN model was carried out by using a chronic constriction injury of the infraorbital nerve (ION-CCI). To screen out the successful animal models and the normal control groups (25in each of group), the mechanical stimulation was used. Acutely isolated TG neurons were used for whole cell patch-clamp recording. ATP, P2X and P2Y receptor agonists or antagonists were perfused to detect the effects on VGCCs currents for analysis its acting pathway.Results In the normal control group, ATP can reversibly inhibit the VGCC currents of TG neurons, about (14.38±1.1)%(n=7, P<0.05). αβ-methylene ATP (αβ-meATP), a P2X receptor agonist, can significantly inhibit the VGCC currents of TG neurons, about (14.29±1.54)%(n=6, P<0.05). However,2-MethylthioADP (2-MeSADP), a P2Y receptor agonist, has no effect on VGCC currents of rat TG neurons (n=7, P>0.05). In the CCI-ION model group, ATP can reversibly inhibit the VGCC currents of TG neurons, about (33.08±3.96)%(n=8, P<0.01). ap-meATP can significantly inhibit the VGCC currents of rat TG neurons, about (25.22±5.02)%(n=6, P<0.01), which can be partly reversed by TNP-ATP, a P2X receptor antagonist.2-MeSADP can inhibit the VGCC currents of TG neurons, about (11.08±1.41)%(n=6, P<0.05). Compared with normal control group, in model group the inhibitory rates of ATP and ap-meATP are significantly enhancement (P<0.05) and activating P2Y receptors can partly inhibit VGCC.Conclusion P2receptors mediate the inhibitory effect of ATP on the VGCC currents in normal rats and ION-CCI rats, and the inhibitory rate of ATP on the VGCC in CCI-ION rats was much more than that in normal rats. P2Y receptors do not participate in the inhibitory effect of ATP on the VGCC in normal rats, but participate in CCI-ION rats. Those results indicate that P2X and P2Y receptors may relate to trigeminal neuralgia.