Riluzole

Riluzole is an anticonvulsant drug and belongs to the family of use-dependent Na⁺ channel blocker which can also inhibit GABA uptake with an IC₅₀ of 43 μM. IC50 & Target: Sodium channel^[1]
IC50: 43 μM (GABA receptor)^[1] In Vitro: Riluzole is an anticonvulsant drug and belongs to the family of use-dependent Na⁺ channel blocker which can also inhibit GABA uptake with an IC₅₀ of 43 μM. At 20 μM, Riluzole inhibits peak autaptic IPSCs only slightly but prolongs IPSCs reliably. It is also found that Riluzole causes a strong, concentration-dependent, readily reversible enhancement of responses to 2 μM GABA. At higher concentrations of Riluzole, especially 300 μM, GABA currents exhibit apparent desensitization during prolonged co-exposure to 2 μM GABA and Riluzole. The EC₅₀ of Riluzole potentiation of GABA responses is about 60 μM^[1]. In Vivo: In normal naïve rats, systemic injection of Riluzole (8 mg/kg, i.p.; n=6 rats) decreases the duration of ultrasonic but not audible vocalizations evoked by noxious stimulation of the knee joint compare to vehicle tested in the same rats (P<0.05). Systemic application of Riluzole (8 mg/kg, i.p.; n=19 rats) decreases the vocalizations of arthritic rats compare to predrug and vehicle significantly (P<0.05 to 0.001). Riluzole administered into the CeA significantly decreases the duration of audible and ultrasonic vocalizations evoked by noxious stimulation of the knee compare to predrug values (n=8 rats; P<0.05 to 0.01)^[2].