ABSTRACT
To investigate the effect of interleukin-1β (IL-1β) on IA and IK currents in cultured murine trigeminal ganglion (TG) neurons, whole-cell patch clamp technique was used to record the IA and IKcurrents before and after 20 ng/mL IL-1β perfusion. Our results showed that 20 ng/mL IL-1β inhibited IA currents (18.3±10.7)% (n=6, P＜0.05). IL-1β at 20 ng/mL had no effect on G-V curve of IA but moved the H-infinity curve V0.5 from -36.6 ± 6.1 mV to-42.4 ±5.2 m V (n=5, P＜0.01). However, 20 ng/mL IL-1β had effect on neither the amplitude nor the G-V curve of IK. IL-1β was found to selectively inhibit IA current in TG neurons and the effect may contribute to hyperalgesia under various inflammatory conditions.
ABSTRACT
The different effects of capsaicin on IA and IK currents in pain-conduct neurons of trigeminal ganglia (TG) were investigated. In cultured TG neurons of rats, whole-cell patch clamp techniques were used to record the IA and IK before and after capsaicin perfused. Results revealed that 1 μmol/L capsaicin could inhibit the amplitude of IA by 48.2% (n=10, P＜0.05), but had no inhibitory effect on IK (n=7, P＞0.05). Ten μmol/L capsaicin could significantly inhibit the amplitude of IA by 93.2% (n=8, P＜0.01), but only slightly inhibit the amplitude of IK by 13.2% (n=7,P＜0.05). Neither 1 μmol/L nor 10 μmol/L capsaicin had effects on the active curve of IA and IK.It was concluded that capsaicin could selectively inhibit the IA current, and this effect might involve in the analgesic mechanisms of capsaicin.
ABSTRACT
To investigate the effects of WIN 55,212-2 on IK in cultured rat trigeminal ganglion (TG) neurons, whole-cell patch clamp techniques were used to record the IK before and after WIN 55,212-2 perfusion at different concentrations. 30 μmol/L WIN 55,212-2 markedly (35.7 %±7.3%, P＜0. 01, n=8) inhibited IK currents, and the currents were partially recovered after washing.30μmol/L WIN 55,212-2 also induced a significant depolarizing shift in conductance-voltage parameters (control: V0.5 =10.43 ± 4.25 mV, k= 16.27±3.86; WIN 55,212-2: V0. 5 =24.71±3.91mV, k =16.69±2.75; n = 8, P＜0.01 for V0. 5). 0.01μmol/L WIN 55,212-2 slightly (27.0 %± 7.9 %, P＜0.05, n=7) increased IK currents, but had no significant change in conductance voltage parameters (control: V0.5 =10. 74±5. 27 mV, k=17. 33±2. 96; WIN 55,212-2: V0.5 =11.06±2.05 mV, k=19. 69±6. 60; n=7, P＞0.05 for V0.5 and k). These results suggested that WIN 55,212-2 has dual action, which might be through different receptors.