Flunanzine Inhibited The High Voltage Active Calcium Currents Of Trigeminal Ganglion Neurons With Sensitization Of Dural Afferents

Objective:The aim of the present study was to investigate the effects of high voltage active calcium currents of trigeminal ganglion neurons modulated by dural afferent nerve endings activated with inflammatory soup and. CGRP. Herein, we report the effects of FLN on calcium currents by using a conventional whole-cell patch clamp technique from acutely isolated rat trigeminal ganglion neurons.Methods:Male adult Sprague Dawley rats were randomly divided into4groups (each group n=8):control group, normal saline treatment group, IS+CGRP infusion group, flunanzine prevention group.1. Polyethylene tube (PE-10) were embedden upon the SSS of each male adult Sprague Dawley rat, next then, rats were given10ul IS or NS once a day in consecutive six days through PE-10tube using Hamilton glass syringes (25ul).2. IS+CGRP infusion groups were given20ul IS(2mM histamine,5-HT, bradykinin and0.2mM prostaglandin E2)+10ulCGRP.The rats in the flunanzine prevention groups were administered intragastrically with flunanzine1.04mg/(kg-d) for a week before modeling, and then were given20ul IS+10ulCGRP.3. After the rats were administered1.5h, mice were killed. We report the effects of calcium currents, using a conventional whole-cell patch clamp technique from acutely isolated rat trigeminal ganglion neurons.4. We investigate the effects of high voltage active calcium currents of trigeminal ganglion neurons modulated by dural afferent nerve endings activated with IS+CGRP and the effects of FLN on calcium currents by using a conventional whole-cell patch clamp technique.5. To determine the impact of PKC, here we used PKC inhibitor (GO-6983) and PKA inhibitor (H-89), to examine its effect on the flunanzine-induced inhibition of calcium currents.Results:We found that the I-V curve was significantly downshifted in IS+CGRP group. Flunanzine was found to inhibit the peak amplitude of Na+currents compared to IS+CGRP group. The potential at which ICa reached a maximum was shifted from0mV to-10mV. For calcium currents, Vg0.5was shifted in the hyperpolarizing direction (normal saline treatment group,-16.3±2.0mV; IS+CGRP group,-20.9±3.2mV;n=12P<0.05).And compared to IS+CGRP group, flunanzine shifted Vg0.5in the depolarizing direction(flunanzine,-18.9±1.5mV; IS+CGRP group,-20.9±3.2mV; n=12, P＜0.05). The steady-state inactivation curve was shifted towards more depolarizing potentials in IS+CGRP group (normal saline treatment group,-22.5±1.4mV; IS+CGRP group,-12.4±1.2mV;n=12P<0.05).And flunanzine shifted Vg0.5in the hyperpolarizing direction (flunanzine,-16.7±2.0mV; IS+CGRP group,-12.4±1.2mV;n=12P<0.05). Application of PKC inhibitor GO-6983and PKA inhibitor (H-89) did not alter the basal calcium current, but it prevented the decrease in calcium currents induced by flunanzine. These results confirmed that flunanzine modulated calcium channels in a PKC and PKA dependent pathway.Conclusion:FLN was found to inhibit calcium currents. Moreover, FLN could shift the voltage-gated activation curve for calcium channel in the depolarizing direction, and shift the steady-state inactivation curve for calcium channel in the hyperpolarizing direction. We also found that PKC inhibitor GO-6983and PKA inhibitor H-89blocked the FLN-induced inhibition of calcium currents. Considering its complex modulatory effects on voltage-gated calcium channels, FLN may have potential effects on the nervous system and lead to a change in excitability of FLN afferent fibers.